How many nuclear submarines have been lost worldwide, as a result of accident or damage?

Eight nuclear submarines have sunk as a consequence of either accident or extensive damage: two from the United States Navy, four from the Soviet Navy, and two from the Russian Navy. Only three were lost with all hands: the two from the United States Navy and one from the Russian Navy. All sank as a result of accident except for K-27, which was scuttled in the Kara Sea when repair was considered impossible and decommissioning was too expensive. Of the eight sinkings, two were caused by fires, two by explosions of their weapons systems, one by flooding, one by bad weather, and one by scuttling due to a damaged nuclear reactor.