Comedian Jay Leno’s farewell Tonight Show drew the late-night program’s biggest audience in more than 15 years. NBC says 14.6 million people tuned in Thursday to see Leno wrap up his 22 years as host of Tonight. The audience was the biggest since May 14, 1998, when Jerry Seinfeld appeared on Tonight to mark the end of his sitcom. That drew nearly 15 million viewers. 63-year old Leno’s first goodbye to Tonight, in 2009, had 11.9 million viewers. Tonight had been averaging less than 4 million nightly viewers in the past year.