A recent study (see below) makes the claim that the Bible is as violent as the Koran. Hence there is no need to worry about with Islam. It is just like Christianity and Judaism.
My only interest is in political violence, not when Cain killed Able. Political violence is when a group attacks those outside of it. It is political when Muslims kill Kafirs in jihad, for instance. This eliminates counting personal violence and internal wars.
We want to measure ideas, so we count more than individual sentences. We need to count all the content that applies to the political violence.