By Lynette Rice
Updated May 28, 2009 at 12:00 PM EDT

Jay Leno, who will step down from The Tonight Show on Friday, has told more than 33,000 jokes about political figures since he took over the late-night spot in 1992, according to a study from the Center for Media and Public Affairs. Leno’s favorite target was Bill Clinton, who was ridiculed more than 4,400 times. George W. Bush, in comparison, was only poked at 2,999 times, the study said. During the same period, Conan O’Brien, who will take over The Tonight Show on June 1, told 7,057 jokes about public figures on his 12:30 p.m. show. Unlike Leno, O’Brien directed most of his teasing toward Bush.

Leno’s favorite non-political subjects were O.J. Simpson (737 jokes) and Michael Jackson (488 jokes). O’Brien also poked fun of Jackson (140 jokes), as well as Paris Hilton (34 jokes). The Center for Media and Public Affairs, which has been monitoring political jokes in late-night TV since 1988, is a non-partisan research organization affiliated with George Mason University in Virginia.