With Lohan as host of “Saturday Night Live” over the weekend, her third such stint in two years, the show averaged just a 5.1 metered-market household rating. That’s down 18 percent from a 6.2 for Lohan’s last appearance on the show, when she hosted last year’s season-ender in May.

It’s also well below the averages posted by less-publicized hosts such as Jack Black, whose appearance with Neil Young in December averaged a 6.1, and Steve Martin, whose 14th hosting gig in February averaged a 7.0.

Why the lesser interest in Lohan this year? Some of the dropoff could be explained by the fact that the show aired the night before Easter, when people travel and are not on their usual schedules.

And certainly household ratings for “Saturday Night Live” in general are trailing, having dipped 6 percent this year, to a 4.5 average. When final ratings are released for Saturday’s show later today, it will likely settle in around or a bit below that mark.

But most likely the answer is that the Lohan craze has peaked. The 19-year-old tabloid queen hasn’t had a hit movie since “Mean Girls” two years ago. Last summer’s “Herbie: Fully Loaded” grossed just $66 million at the box office, $20 million less than “Girls,” despite having more than double the budget.

Once a staple of internet search lists, taking 10th place on Yahoo’s year-end search terms last year, Lohan doesn’t even appear in the site’s top 20 this week.

Perhaps people are simply tired of Lohan, whose rumored anorexia, problems with her troubled father, and ever-changing love life have made her a staple in celebrity magazines such as Us Weekly, In Touch and Star.

In what’s usually a sign that a celebrity knows she has an image problem, Lohan recently announced plans for a charity trip to Kenya, which her spokesperson immediately hawked on MTV. 

Meanwhile, in other daypart ratings for the week ended April 16:

Among morning shows, NBC’s “Today” held a healthy 1.2 million lead over ABC’s “Good Morning America,” with an average 6.0 million. CBS’s “Early Show” was well behind at 2.8 million.

NBC also held its lead among Sunday morning shows, with 3.99 million viewers for “Meet the Press,” some 1.3 million more than CBS’s “Face the Nation” or ABC’s “This Week with George Stephanopoulos,” both with just over 2.6 million.

In late night, NBC’s “Tonight Show” averaged 6.3 million total viewers, trouncing ABC’s “Nightline” at 3.6 million and CBS’s “Late Show” with 3.3 million. NBC’s “Late Night” averaged 2.4 million, 600,000 ahead of “Late Late Show” on CBS and 800,000 ahead of ABC’s “Jimmy Kimmel Live.”

And NBC kept its lead in a down week for nightly newscasts, for the week ended April 16. “Nightly News” averaged 7.98 million total viewers to 7.23 million for ABC’s “World News Tonight” and 6.78 million for CBS’s “Evening News.”

In syndication for the week ended April 9, “Wheel of Fortune” was the top show with an 8.4 household rating. “Oprah” was the top talk show as usual with a 6.0. And “Everybody Loves Raymond” was the top comedy with a 5.8 average.