A significant drop in Chinese viewers pushed down Formula One's global television audience last year.
"The majority of our established markets brought larger audiences throughout 2012 than they delivered in 2011," said Formula One chief Bernie Ecclestone.
"A small handful of territories didn't meet expectations in terms of reach, with the Chinese market suffering a decrease which could not be absorbed by a significant number of increases elsewhere," he added.
"Overall, the audience remains at well over half a billion viewers globally."
A total of 229 hours was broadcast in 2012 in China, compared to 322 in 2011, which led to the overall reach dropping to 48.89 million viewers from a previous 74.5 million.
The 2012 report did not give a precise figure for the global audience, which was 515 million in 2011.
Television coverage of the sport was aired in 185 territories by 110 broadcasters.
Brazil was the sport's largest market by both reach and average audience with 85.55 million people in total tuning in to watch a record 20 races.
The 2013 season starts in Australia on 17 March.