The majority of jokes aired on late-night comedy shows targeted Republican Senate candidates, a study by a conservative media watchdog group finds. 

Media Research Center analyzed four daily late-night comedy shows from Sept. 8 through Oct. 29. The shows were Comedy Central’s "The Daily Show," ABC’s "Jimmy Kimmel Live!," and NBC’s "The Tonight Show Starring Jimmy Fallon" and "Late Night with Seth Meyers." 

According to the analysis, 87% of jokes about Senate candidates were directed at Republicans.

The comedy shows told 45 jokes about Republican Senate candidates during the study period. Targets included Texas candidate Ken Paxton, Maine candidate Susan Collins and Michigan candidate Mike Rogers. 

"Late-night comedy has become remarkably predictable. When the same people are always the punchline, and the same people are almost never the punchline, eventually the pattern becomes funnier than the jokes. Comedy is sharpest when nobody is off limits. Late night should try it," David Bozell, president of Media Research Center, said in a statement.