Up until 2014, Islamic terrorism made up around 1% of all terrorist attacks in the EU according to Europol report data. In 2015 that number spiked to 5% with all the attacks that year. I imagine that number will be even higher for 2016 when those figures are released in a few months. But yeah, that isn't anywhere near the figure you pulled out of your ass. In fact, the reverse is true. Here are a few of the reports if you're interested. If you're not willing to sift through 60 odd pages, scroll down to the tables and do the math yourself.
2015
2014
2013