Last year more than 3,800 personnel were on board vessels that were under pirate attacks.
At least 35 hostages died from the hands of Somali pirates for 2011, despite the fact that the number of prisoners taken dropped to 555, compared with 645 in 2010, information by the One Earth Future foundation and the International Maritime Bureau.
The report has been made public to mark the IMO's annual Day of the Seafarer.
The death toll includes 8 known to have been killed by their captors either during a attack attempt or later put to dead by pirates and a further 8 died of lack of food or disease.
The report says that the others were killed either during rescue tries by military forces or while running from the pirates.
Despite of this information on previous years can't be trusted, the total of 35 almost exactly represents the highest number of piracy-related fatalities in one year.
According to the information 149 hostages had now been held for more than 12 months, it was told, with 26 held for more than 24 months.
Many of those freed declared abuse that included beatings, removal of fingernails and dumping in the open sea. More than 40% of taken hostages told that have been used as human shields at some point while being held hostages.
Most attacked people were from developing nations, especially the Philippines, India and China and from Gulf and African states.
Pirates are becoming more and more violent, according to the information.
Dead pirates number also appear to be rising, with facts of at least 111 killed in 2011, some 70% of them in clashes with military forces.