Possibly the same reason why half a dozen other most popular pages (for all periods) have 'XXX' in them—from those Vin Diesel films (one of which holds the 18th most visited in Yearly), to a beer brand.
That along with the other triple X in the searches makes me think about high hormones teenager trying to search for something specifically and they have parental controls on their computer.
He has a large and fanatical fanbase despite having trapped his pregnant girlfriend in a room and beating her so severely her eyes swelled shut (which he would later brag about)... while out on bail for breaking into someone's house, pistol whipping them, and robbing them.
As long as he's on the list, he's not dead.
I don't know much about rap, but I do know that dying young makes you very popular. When I was a teenager it was tupac.