Key Findings:
Sequels have take over $20bn at the box office in the past quarter of a century. The highest grossing series of films is the Star Wars franchise, the five movies earning $1.4bn at the US box office and the sixth movie keenly awaited by exhibitors and the public alike in 2005.

This decade is the most successful ever seen for movie sequels. The average annual box office per year has been climbing steadily since the 1980s, to stand at $1.9bn for all sequels in the 2000s, compared with $718m in the 1990s.

First movies in a series took 38 percent of total sequel revenues earned at US box office. The second movie (or the first sequel) accounted for 36.1 per cent of total box office revenues, indicating that an average sequel performs only marginally poorer at the box office than the original film.

Action films account for the highest number of sequel releases, some 51 movies or 29.8 per cent of all sequels. However, sci-fi is probably the most successful sequel genre. Not only does one series extend to 10 movies (Star Trek), the average revenues earned by the second title are an impressive 46.1 per cent above the first.