Viewers continue to flock to Jay Leno as he wraps his “Tonight Show” stint, with his final full week drawing the program’s largest audience since the comic returned as host nearly four years ago.

Nielsen estimates that an average nightly audience of 4.99 million viewers tuned in to “The Tonight Show with Jay Leno” during the week of Jan. 27-31 — up about 30% from the comparable week a year ago — as it crushed its ABC and CBS competition. CBS’ “Late Show With David Letterman,” which aired a few repeats during the week, averaged about 3 million, and ABC’s “Jimmy Kimmel Live” drew about 2.4 million.

The last time Leno drew more viewers in a week was March 1-5, 2010 — his first week back for his second stint in the host’s chair of “The Tonight Show.”

Through 19 weeks, “Tonight” is enjoying its most-watched season in five years. And Leno exits “Tonight” on a 67-week winning streak in total viewers against rival Letterman’s CBS show.

In adults 18-49, “Tonight Show with Jay Leno” last week had its best showing (1.42 million viewers) since November 2010, and is enjoying its best season in three years.

Guests during Leno’s final full week included Tim Allen, Dana Carvey, Miley Cyrus, Bill Maher and Wanda Sykes. Billy Crystal and Garth Brooks are among the guests tonight for  his final show.

Of course, heir-to-the-throne Jimmy Fallon is doing very well too, with his “Late Night” average of 2.38 million viewers last week about 30% higher than a year ago and its best since May 2009 (the final week before Conan O’Brien took over “Tonight” hosting duties from Leno).