Maritime Piracy: Up, Down or Sideways?

Has maritime piracy increased or decreased over the last five yearsbetween 2003 and 2008? If you said decreased, you cheated, because 99% people would have said increase. The truth, however, is otherwise, as the following figure shows:


[via DLC]

[Update] As a reader rightly points out, the priacy decline looks like it will come undone in 2009 because of over-enthusiastic ship-jacking in the Gulf of Aden.