Europol publishes an annual report entitled EU Terrorism Situation and Trend Report.
The results are stark, and prove decisively that not all terrorists are Muslims. In fact, a whopping 99.6% of terrorist attacks in Europe were by non-Muslim groups; a good 84.8% of attacks were from separatist groups completely unrelated to Islam. Leftist groups accounted for over sixteen times as much terrorism as radical Islamic groups. Only a measly 0.4% of terrorist attacks from 2007 to 2009 could be attributed to extremist Muslims.
On p.7, the 2009 Europol report concludes:
Islamist terrorism is still perceived as being the biggest threat worldwide, despite the fact that the EU only faced one Islamist terrorist attack in 2008. This bomb attack took place in the UK…Separatist terrorism remains the terrorism area which affects the EU most. This includes Basque separatist terrorism in Spain and France, and Corsican terrorism in France…Past contacts between ETA and the FARC illustrate the fact that also separatist terrorist organizations seek cooperation partners outside the EU on the basis of common interests. In the UK, dissident Irish republican groups, principally the RIRA and the CIRA, and other paramilitary groups may continue to engage in crime and violence.