NEW YORK (CNN/Money) - This year's World Series had everything baseball could want except viewers, as an initial reading of television viewership shows this will be the worst-rated series in history.

Fox, which broadcast the series, released a reading of national ratings it received from Nielsen on an expedited basis that shows a strong viewership for Sunday night's deciding Game 7, but far below last year's Game 7.

The game had a 17.9 rating, which represents the percentage of homes that watched the game. It had a 28 share, equal to the percentage of homes which were watching television that were tuned into the game. The rating marked Fox's best Sunday evening showing since the most recent Super Bowl, and beat the other three major networks combined in the key viewership group age 18 to 49.

Ratings looked to be the worst ever, despite a thrilling seven-game series.

But both the rating and the share are more than 24 percent below comparable numbers from Game 7 a year earlier. In fact, each game of the World Series between the Anaheim Angels and San Francisco Giants trailed year-earlier viewership numbers for the contest between the New York Yankees and Arizona Diamondbacks, as the overall series rating also showed a 24 percent decline.

Fox executives wouldn't confirm what ratings they were promising advertisers, but David Miller, analyst with Sanders Morris Harris, said that Fox had promised an average 16 rating for the first six games and about at least a 24 rating for Game 7 if it was played. Fox's figures show an average rating of 10.9 over the first six games. The low ratings means that Fox will have to give free ad time to some of the advertisers. Shares of Fox Entertainment Group (FOX: Research, Estimates), fell 38 cents to $24.47 in trading Monday.

Fox said that the network will finish ahead of its business forecast for the Series. But that business forecast has to be somewhat conservative and could not count on a seven-game series, which normally builds more interest by the time it reaches its conclusion. The low rating for a seven-game series was a disappointment for the company, which earlier this year took a $225 million charge for anticipated losses from its Major League Baseball broadcast deal from this season through 2007.

"While the viewership was not as high as we had hoped, the fact is that Fox won six of the seven nights World Series games were played, won the week in households and adults 18-49 (years old)," said a statement from Fox Sports President Ed Goren.

The series needed about a 22 national rating in Sunday's game to beat the average rating of the five-game 2000 World Series between two New York teams -- the Yankees and Mets -- which had a record-low 12.4 rating. Fox points out that the average viewers per game is slightly higher than two years ago due to the growth in the number of viewers estimated by Nielsen ratings service.

The series was considered an exciting one, with five of the games coming down to the last pitch with the tying or winning run at the plate, and four come-from-behind victories. But the regional nature of the contest and the length of the games are considered part of the reason for the low rating.

Fox's statistics show that Eastern time zone ratings were only 9.9 average for the series, down 35 percent from a year ago, and in the Central time zone it was only 11.8, down 17 percent. About 49 percent of the nation lives in the Eastern time zone, and about 29 percent live in the central time zone.

The Pacific time zone saw ratings of 18.3 outside of the teams' home markets of Los Angeles and San Francisco, up 6 percent from a year earlier. The L.A. market had a 42.0 rating and a 61 share Sunday night, while the San Francisco market had a 41.5 rating and a 62 share.

This summer's labor strife between owners and players, who nearly went on strike before reaching an eleventh-hour contract agreement, also has hurt fan interest, according to Fox Sports Chairman David Hill.

"Once again, baseball managed to turn off its loyal fans," Hill told Associated Press Saturday before Game 6 of the World Series. "I hoped it would pick up when we got to the postseason. It certainly hasn't been what I hoped it would be."