That table is from Rummel's book, 'Death by Government'.
An excellent, and depressing, read. All those useful idiots advocating for banning private gun ownership should be required to read this book - and then decide if they really want to put all of their trust in the Government.
Reading the Bible would be better ('the heart of man is deceitful above all things, and desperately wicked' - and we are to Trust only in God), but that requires a heart to receive the Truth. Rummel's book just states the cold facts about the brutal actions of many Governments in the 20th Century (through the 1970s -- it left out a lot of the butcheries from 1980 to 1999) - and would provide a useful frame of reference, and education, for these 'kids' walking out of their classrooms.
I read Rummel’s Death By Government when it was first published. Changed my outlook on government completely.