Box-office figures for 2011 released this week confirmed the inevitable. The five most successful movies in America last year were all part of existing film series of one type or another:

1. Harry Potter and the Deathly Hallows — Part 2 ($381 million)

2. Transformers: Dark of the Moon ($352 million)

3. The Twilight Saga: Breaking Dawn - Part 1 ($276 million)

4. The Hangover Part II ($254 million)

5. Pirates of the Caribbean: On Stranger Tides ($241 million)

There are a few other numbers worth considering, however, such as 1.28 billion, the number of times people in North America went to the movies last year. That figure is down 4.4 percent from 2010, and it's the lowest movie viewership since 1995. Are moviegoers weary of sequels or just short on cash? That question should inspire much industry debate in 2012.