NEW YORK — Contestants are disappearing as the "American Idol" finale approaches. Unfortunately for Fox, so are the viewers.

The 21.8 million people who watched last Tuesday's competition was the show's smallest Tuesday audience in more than five years. The show did better the next night, with 22.9 million, but that was the smallest Wednesday audience in three years, according to Nielsen Media Research.

They were still the most popular programmes in prime-time last week. Even though it is the May ratings "sweep," no other show cracked the 20 million viewer mark, once considered routine for television's top programmes.

Another one-time big event, the finale of a "Survivor" season on CBS, was seen by 13 million viewers and didn't crack Nielsen's top 10.

Americans also preferred to spend Mother's Day with their own moms, if possible. NBC's special "America's Favorite Mom," ranked number 107 for the week with just 2.4 million viewers.

CBS was the nation's most popular network last week, averaging 10.6 million viewers in prime-time (6.7 rating, 11 share), followed by ABC with 9.5 million (6.2, 11). Fox won among the 18- to 49-year-old demographic but, reflecting the "American Idol" decline, slipped to third among all viewers with an 8.9 million average (5.5, 9). NBC had 6 million viewers (4.0, 7), the CW had 2.6 million (1.7, 3), My Network TV had 1.2 million (0.8, 1) and ION Television had 410,000 (0.3, 0).

Among the Spanish-language networks, Univision led with 3.6 million viewers (1.8, 3), Telemundo had 950,000 (0.6, 1), TeleFutura had 640,000 (0.3, 1) and Azteca had 130,000 (0.1, 0).

ABC's "World News" won the evening news ratings race, averaging 8 million viewers (5.5, 12). NBC's "Nightly News" had 7.8 million viewers (5.4, 12) and the "CBS Evening News" had 5.6 million (3.9, 8).

A ratings point represents 1,128,000 households, or 1 percent of the nation's estimated 112.8 million TV homes. The share is the percentage of in-use televisions tuned to a given show.

For the week of May 5-11, the top 10 shows, their networks and viewerships: "American Idol" (Wednesday), Fox, 22.87 million; "American Idol" (Tuesday), Fox, 21.76 million; "Dancing With the Stars" (Tuesday), ABC, 18.38 million; "Dancing With the Stars" (Monday), ABC, 18.11 million; "CSI: Crime Scene Investigation," CBS, 18.07 million; "Grey's Anatomy," ABC, 16.02 million; "Desperate Housewives," ABC, 15.42 million; "Without a Trace," CBS, 14.67 million; "CSI: Miami," CBS, 14.11 million; "NCIS," CBS, 13.6 million.