(AP) -- The amount of time people spend on the computer while watching TV is going up sharply.
The Nielsen Co. said Monday that people who multitask this way spent an average of three and a half hours doing so in December. That's up sharply from the two hours, 29 minutes that Nielsen reported only six months earlier.
The percentage of TV viewers who do this isn't going up that fast. That increased by 57 percent to 59 percent during the same period. But those who are doing it spend much more time at it.
Television executives have pointed to this trend to help explain why big events like the Oscars, Grammys and pro football playoffs have been doing so well in the ratings - people watching and making comments to their friends through social Web sites like Twitter and Facebook.
Explore further: US teens spend more time watching TV than on computer