Google
Just typing rappers names in to the search engine (enclosed by quotes):
mind you this only reflects this period in time obviously Nov. 14 2006
You may be surprised by some of these
Eminem gets 36,600,000
Snoop - 23,300,000
DMX 12,700,000
2pac gets 8,170,000
Jay-Z - 7,370,000
Black Eyed...