In a fresh sign of rising violence at sea, pirates this week hijacked a cargo ship in the Gulf of Aden near Somalia and took all 25 Filipino crew members hostage. The attack came as a global maritime watchdog issued a report saying that 2010 marked a record year for pirate attacks. Here is a guide to the threat, by the numbers:

Number of pirate attacks around the world in 2010, a 10 percent rise over 2009

Number of vessels captured by pirates worldwide last year

Number of those ships that were captured off of Somalia

Hostages captured by pirates and held for ransom in 2010

Number of those hostages who were captured in attacks off the coast of Somalia

Ships still in the hands of pirates (including four seized since 2011 began)

Number of crew members still held hostage

Victims killed in pirate attacks in Somali waters in 2010, twice as many as in 2009

Hijackings averted worldwide when crews took refuge in reinforced rooms or "citadels," a recommended practice for discouraging piracy

$5.4 million
Average ransom paid to Somali pirate groups last year, up from $150,000 in 2005, according to a recent report from a non-governmental group called One Earth Future

$238 million
Total ransom paid in 2010, according to the report

$7 billion to $12 billion
Total annual cost of piracy to businesses and governments. That includes the cost of ransoms, insurance premiums, naval forces, security equipment, and other related costs.

Sources: Bloomberg, CNN, Cyprus Mail, International Maritime Bureau, MSNBC, NY Times