I stumbled upon this post on FrontPageMagazine about the number of terrorist-attacks being quadrupled since 2001. Because I also write on a sister website of this blog Emperors and clothes about science (in Dutch, but Google Translate gives a good impression of what is going on there) I felt compelled to mention it here and to add some reflections of my own.
The FPM-article does not include this picture or the one you find below. I made this Excel-graph, based on the list of 'The Religion Of Peace' (TROP). The above picture needs some elucidation. I will provide this but first I make some remarks about the data to which the FPM-article refers.

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Kerry Patton wrote his post because

Today, it is known via the University of Maryland’s Global Terrorism Database, deaths caused by terror have decreased yet attacks have actually quadrupled world-wide since 2001.

You can find this database here and here is their 'about'-page. It claims:

Contains information on over 104,000 terrorist attacks, Currently the most comprehensive unclassified data base on terrorist events in the world, Includes information on more than 47,000 bombings, 14,000 assassinations, and 5,300 kidnappings since 1970, Includes information on at least 45 variables for each case, with more recent incidents including information on more than 120 variables, Supervised by an advisory panel of 12 terrorism research experts, Over 3,500,000 news articles and 25,000 news sources were reviewed to collect incident data from 1998 to 2011 alone

Quite impressive

..defusing an ideology is more realistic than shutting out a tactic

and you can really dig into details. Being born in Schiedam I am amazed to find an organization called 'Schiedam Youth Front' in the list of perpetrators. Back in 1986 there was one attack or incident by this group that caused one casualty.

The imperative of ideological battle
It shows that GTD indeed gathers detailed information, but on what? Patton:

Terrorism is a tactic used by individuals with specific ideologies. Killing an ideology is nearly impossible. The war on terror is a complete misnomer. A war cannot be waged against a tactic.

I disagree with Patton's claim about the impossibility to defuse an ideology: it is hard, in the case of muhammedanism it is very hard, but it is not impossible. At least it is much more realistic than shutting out a tactic.
In this e-book essay Islamophobia, Defying the Battle Cry I introduced an alternative formulation of Clausewitz's famous assertion about politics and war:

Those who refuse to fight the ideological and political struggle to cope with a hostile ideology, increase the risk of (civil) war.

The website TROP is definitely part of the ideological fight while clearly stating:

We strongly condemn any attempt to harm or harass any Muslim anywhere in the world because of their religion. Every human being is entitled to be treated as an individual and judged only by his or her own words and deeds.

A huge disadvantage of the GTD is that it does not group the perpetrators. You can select any number from the list of perpetrators but this means you have to know all of them to know if they should be included in a certain category, be it violent animal-right-activism or muhammedan holy war. I went through the list of perpetrators and included the groups I was quite sure that belong to the last category and GTD came up with this graph:
Surely it underlines Patton's claim that the number of attacks has quadrupled since 2001. (Note that the number in 2001 already had more than quadrupled since the seventies and eighties). To get the numbers of people killed by muhammedan terrorism from the Maryland database takes even more work.

Terrorism vs terror
Muhammedan terror would give much higher numbers, of course. GTD's codebook (download pdf) explicitly mentions that state-terror is excluded: so the hanging of homosexuals or stoning for adultery in Iran are not in the numbers.

Muhammedanism is a culture of threat

No victims of 'honor killings' nor Female Genital Mutilation -even of the terrifying type III at an age the girls will remember the ordeal- are counted.
Muhammedanism is a culture of threat. On numerous places in the Quran even 'the faithful' are denominated as 'the fearing'. The culture of threat based on the disgusting muhammedan theories on blasphemy and apostacy are strongly underrepresented in the numbers of GTD at least.
These numbers are also underrepresented in the data of TROP. Still, those numbers are much higer than in this GTD-graph: according to their data from 2002 tot 2011 the number of attacks have increased from 564 to 2039. The trend is about the same however. When you take the extrapolation for 2012 into account TROP's numbers show a little more than quadruplication

Trends and trendlines
According to the TROP-statistics since 2001 over 100.000 people were murdered by jihadists. Still, from a political point of view, the trend is even more important than the numbers per se.
Many people acknowledge part of the terror and terrorism problems related to muhammedanism but argue that as time passes they will fade away. Sometimes this is accompanied with an implicit or explicit reference to problems that were connected with religions -like christianity or hinduism- decades or centuries ago. Granted that it is hard to fight and defuse an ideology, especially when the most important powers built on it are based in another part of the world: in assessing its threat it makes a huge difference if the trend is up or down.
First I want to emphasize that I am not interested in giving the most accurate prediction of the number of victims in 2013 or 2022: I want to understand what is happening in the world and these numbers give important but certainly not exclusive or decisive information about it. I am annoyed by the makers of the GTD deliberating about whether blunt objects to hurt or kill victims should be in the same category of weaponry as sharp objects or not while at the same time excluding the 'color' of the 'political or religious' motive as category.
The solid lines in blue, red and green give a clear indication of the trend. The dashed and dotted lines are 'trendlines', but these lines are constructed through different mathematics. Distilling trends and more specifically the type of trend from raw data is useless without some explicit idea, some theory about the variation.
The dashed red line is drawn based on the assumption of exponential change. The straight line that would represent a linear change in this case is not very different. The purple line is a little different. It is based on the number of attacks: the blue line. I multiplied with the average number of casualties (15). This has two consequences for the prominence of the line: it is bit more similar to red and green lines and the recent rise look even more worrying. So it underlines my point that the trend is indisputably up. But isn't this a dubious kind of massaging the data?
I think not.

It corrects for the success and thus focuses on the intention of the perpetrators

What it does is that it corrects for the number of people that are killed on the average per attack. What does that mean for what is going on in the real world? It corrects for the success, the efficiency of the attack, and thus focuses on the intention of the perpetrators. And that is what should be done, from a wiser political point of view: fighting a tactic is claptrap, we face an ideology.

Exponential rise
One could argue that a clear decrease of the average number of fatalities per attack reflects the result of anti-terror actions. This might be true but only stems hopeful when you think the tactic is the problem, not the ideology of terror.
Why an exponential change? For some interrelated reasons I think it is correct to use this type of trend. The GTD graph strongly suggests the exponential change: in both the last two periods of 10 or 11 years the numbers quadrupled. Roughly the same goes for the first period.
The first boost for the jihadist ideology originated in the Arab loss of their wars with Israel in 1967 and 1973. Secular forces were rather strong in the Arab countries thanks to the communist/socialist influence: part of the cold war division of the world. The jihadists grabbed the opportunity offered by the military failure of the secular rulers vis a vis the ultimate villains in the eyes of Mohammed and his followers -jews who do not behave like people 'brought low', 'subdued' or 'humbled', as per verse 9:29 of the Quran- and their influence started to grow again after being in decline for centuries.
The greatest victory for the salafi's and jihadist's was the amazing success of pressuring Western countries via the oil crisis. Since that time muhammedanism in effect is being encouraged in and by the West. The western reactions on the Rushdie-fatwa, on the orchestrated cartoon-riots, the support for the islamists in Turkey, neglecting the deceptive nature of the OIC-discourse, misjudging the Arab 'spring' etc all were doubtful.
The strongest boost of course came with the tremendous success of the 9-11 attacks immediately followed by the claim by Bush II:

The terrorists practice a fringe form of Islamic extremism that has been rejected by Muslim scholars and the vast majority of Muslim clerics; a fringe movement that perverts the peaceful teachings of Islam.

(Source: CNN. A few years ago there was a link to this speech on the site of The White House: http://www.whitehouse.gov/news/releases/2001/09/20010920-8.html. This appears to be gone.)
Shortly after this speech the Taliban were ousted from power in Afghanistan. So yes, the West did react on acts of terrorism but simultaneously empowering muhammedanism by actively disregarding its core ideas of terror. Western reactions on acts of terror, raging, wining and demanding from muhammedans have the effect of further encouraging the terror, raging, wining and demanding: hence the exponential character of the trend.
It is possible to calculate a trendline from the data with the shape of the green dotted line by assuming a polynome of the second degree. Such a trend would be supportive for the idea that as time passes muhammedan-related problems will fade away. However calculating the trendline this way, can only be based on wishful thinking. We should refrain from doing that.