The writers of "The Simpsons" went on strike together with the Writers Guild of America at the end of 2007. The broadcasting of "The Simpsons" was not affected by the strike. Since it takes a long time to produce an episode of an animated show, the episodes are written up to a year in advance. So the strike would have had to go on for a while for the show to have run out of new episodes. Production of season 20 was further delayed because of contract negotiations with the six main voice actors. The dispute was resolved, and the actors' salary was raised to $400,000 per episode. The delay in production has caused the planned 22 episodes to be shortened to 20.