This year's World Series between the Washington Nationals and Houston Astros went seven games but finished as the third-least viewed.
The Series averaged 13.91 million viewers, Nielsen said Thursday, down 1.3% from 14.1 million last year for Boston's five-game victory over the Los Angeles Dodgers. The first title in the 51-year history of the Nationals-Montreal Expos franchise averaged an 8.1 rating and 16 share.
The lowest-rated Series remains 2012, when San Francisco's sweep of Detroit averaged a 7.6 rating and 12.64 million viewers. Philadelphia's five-game win over Tampa Bay in 2008 averaged 13.19 million.
The Nationals' 6-2 victory in Game 7 on Wednesday night averaged 23,013,000 viewers according to Nielsen. That's down 18.5% from the 28.42 million average for the 2017 Game 7 between the Astros and Los Angeles Dodgers.
Wednesday's viewership peaked at 27.1 million during the final inning (11-11:15 p.m. EDT).
Those viewership numbers are on par with the 23.52 million that watched San Francisco's Game 7 victory over Kansas City in 2014.
Fox said postseason games on Fox and FS1 averaged 7.84 million, a 12% increase from last year. Fox and FS1 had the American League Division and Championship Series, which has been the more-viewed of the two leagues in recent years.