Funny you ask. I dont have every year memorized so I looked it up. It just so happened that Obama initially followed the trend downward, until he was a lame duck. Then he went against what Congress told him was a bad idea and used executive orders to screw up our justice system. Criminals knew they could get away with it so they started raping and murdering and pillaging. That all stopped when Trump got in office because they knew he wouldn't stand for it, just like illegal immigration declined 76%, and Russia quit invading other countries. Hell, he even got Pyongyang to play nice and open up to diplomacy.
Trump has been the president of no new wars, lower murder, the best economy ever, and less rapes. I think those are good things. Somebody should throw a party.