Jay Leno wraps his 'Tonight Show' run with 14.6 million viewers, his biggest overall audience since 1998

It's the top 'Tonight Show' in total viewers since the night of the 'Seinfeld' finale in May 1998, and Leno's fourth-biggest 'Tonight' ever

Jay Leno concluded his run as host of "The Tonight Show with Jay Leno" Thursday by delivering the show's biggest overall audience in more than 15 years, since May 1998.

Leno averaged 14.637million viewers overall and a 3.8 rating in adults 18-49 in fast-official "live plus same day" ratings from Nielsen Media Research, representing the biggest "Tonight" overall audience since May 14, 1998, the night of the "Seinfeld" finale when Jerry Seinfeld appeared as a guest on the show (14.962 million). In adults 18-49, the 3.8 rating is the top "Tonight" since Jan. 22, 2010, Conan O'Brien's last night hosting the show (4.4). The 18-49 rating is the highest for a Thursday "Tonight" since March 19, 2009 (appearance by President Barack Obama, 3.8).

The average audience of 14.6 million is the fourth biggest ever for a "The Tonight Show with Jay Leno." The top four telecasts in total viewers are: May 20, 1993 ("Cheers" finale, 22.4 million); May 25, 1992 (Leno's debut, 16.1 million); May 14, 1998 ("Seinfeld" finale, 15.0 million); and Feb. 6, 2014 (Leno's final telecast, 14.6 million) (list excludes a brief post-Olympic telecast in 1996).

The final "Tonight Show with Jay Leno" was up 283 percent, nearly quadrupling the show's season average in total viewers, 3.822 million ("live plus same day") heading into this week, and last night's 3.8 rating more than quadrupled the show's season average in adults 18-49 (3.8 vs. 0.9, L+SD).

"Late Night with Jimmy Fallon" followed last night's "Tonight Show" with 6.014 million viewers overall, the show's biggest audience since a special 11:56 p.m. ET telecast on Super Bowl Sunday, Feb. 5, 2012, which averaged 6.087 million viewers.

Counting just regularly scheduled weekday telecasts of "Late Night with Jimmy Fallon," the 6.0 million is a series record, and is the biggest overall audience for the "Late Night" franchise since June 25, 1993 (the final David Letterman-hosted episode, 7.521 million).

In adults 18-49, last night's "Late Night" scored a 2.0, the second-best 18-49 rating ever for "Late Night with Jimmy Fallon," behind the post-Super Bowl telecast on Feb. 5, 2012. It was the highest-ever regularly scheduled Fallon-hosted "Late Night" in 18-49, and highest regularly scheduled episode in the "Late Night" franchise since May 6, 2004 (night of the "Friends" finale, 2.7).

Fallon's 2.0 more than tripled the show's 0.6 season average in adults 18-49 heading into this week. Last night's telecast was up 215 percent versus the "Late Night" season average of 1.909 million in total viewers (L+SD).

Guests on "Tonight" Thursday included Billy Crystal and Garth Brooks, with appearances by Oprah Winfrey, Jack Black, Carol Burnett, Sheryl Crow, Jim Parsons, Kim Kardashian and Chris Paul. Appearing in taped messages were Fallon, Bob Costas, Steve Carell, Olivia Wilde, Miley Cyrus, Martha Stewart, Matt Damon, Mark Wahlberg, Charlie Sheen, Tyler Perry, Bill Maher, Kevin Hart, Dana Carvey, Larry the Cable Guy and President Barack Obama.

 "Late Night" featured Colin Farrell, Chris Pratt and musical guest 2 Chainz.

In adult 18-49 rating, last night's program averages in these "live plus same day" fast-official ratings are, from 11:35 p.m.-12:35 a.m. ET: "The Tonight Show with Jay Leno," a 3.8 rating; CBS's "Late Show with David Letterman," 0.5; and ABC's "Jimmy Kimmel Live," 0.7. In total viewers, last night's program averages are, from 11:35 p.m.-12:35 a.m. ET: "The Tonight Show with Jay Leno," 14.637 million; CBS's "Late Show with David Letterman," 2.423 million; and ABC's "Jimmy Kimmel Live," 2.362 million.

In national averages heading into this week, Leno has been delivering his highest 18-49 viewership at this point in a TV season in three years, and the biggest season in total viewers for "Tonight" in five years. At 12:35 a.m. ET, Fallon is at a four-year high at this point in the season in viewers 18-49, while in total viewers, Fallon is delivering his top average at 19 weeks into the season in the five years he's been hosting "Late Night."

Versus the first 19 weeks of the year-ago season, Leno is up 10 percent in 18-49 viewers (with 1.158 million vs. 1.057 million) and up 11 percent in total viewers (3.948 million vs. 3.570 million). Fallon is up 20 percent in 18-49 viewers (815,000 vs. 682,000) so far this season, and up 17 percent in total viewers (2.012 million vs. 1.719 million).

"Last Call with Carson Daly" is also delivering sizable gains versus the first 19 weeks of last season, up 19 percent in 18-49 viewers (436,000 vs. 365,000), and up 11 percent in total viewers (975,000 vs. 877,000).