Attacks on vessels fell to 264 in 2013, down 40% since the2011 peak in the Indian Ocean.
Only 15 incidents were reported off Somalia last year, down from75 in 2012 and 237 in 2011.
But more than 300 people were still taken hostage at sea in2013, with 21 injured.
Hijackings dropped to 12, 202 ships were boarded and 22 werefired on.
Nigerian pirates are now the main concern, killing one crewmanand kidnapping another 36.
