Two decades ago was a very quiet time for Europe in terms of terrorist attacks. The groups you cite, which are anyhow a totally different problem than Islamist terror, had mostly died down. The number of Islamist terrorist groups in the world has been increasing since the 80s and attacks on the West have been rising again since around the turn of the century. The recent spike is severe. What's most alarming about the current wave is that they are lone wolf attacks that defy our traditional capabilities to uncover plots before they are executed. ISIS has decentralized terrorism.