Since 2007, Europol has issued an annual report on terrorism in the EU.

See https://www.europol.europa.eu/latest_publi... and subsequent years

The stats for the EU countries added up:

('Islam'=Islamist; 'Separ'=separatist; 'Left'=left wing and anarchist'; 'Right'=right wing; 'Single'=single-issue; NotSpec=other or not specified)

Attacks (attempted and successful):
	Islam	Separ	Left	Right	Single	NotSpec	Total
2006	1	424	55	1	-	17	498
2007	4	532	21	1	1	24	583
2008	0	397	28	0	5	11	515
2009	1	237	40	4	2	10	294
2010	3	160	45	0	1	40	249

Arrests:
	Islam	Separ	Left	Right	Single	NotSpec	Total
2006	257	226	52	15	-	-	706
2007	201	548	48	44	-	0	1044
2008	187	501	58	0	3	4	1009
2009	110	413	29	22	2	11	587
2010	179	349	34	1	0	48	611
(UK arrests not classified, so total higher than parts)

Trial verdicts
	Islam	Separ	Left	Right	NotSpec	Total
2007	198	214	27	1	9	449
2008	190	155	27	2	10	384
2009	268	89	39	1	11	408
2010	201	84	37	4	6	332

Convictions (not classified)
2006 257
2007 221
2008 272
2009 337
2010 241

As you can see, most attacks have been separatist, and the majority of arrests in most years too. In the last 2 years, trial verdicts have been mainly in Islamist cases, but still by no means an overwhelming majority. The number of actual Islamist attacks has been very small. In previous years, there have been a very few high casualty Islamist attacks.

Simply, one should not leap to conclusions about terrorist acts.