[['vessel', 'origin', 'type', 'in service', 'unit'], ['oliver hazard perry class', 'united states', 'frigate', '2', 'anti - submarine unit'], ['kobben class', 'norway', 'submarine', '4', 'submarine unit'], ['kilo class', 'soviet union', 'submarine', '1', 'submarine unit'], ['orkan class', 'east germany', 'fast attack craft', '3', 'missile vessels unit'], ['tarantul class', 'soviet union', 'corvette', '2', 'missile vessels unit'], ['project 888', 'poland', 'training ship', '1', 'support unit'], ['project 281', 'poland', 'rescue ship', '2', 'support unit'], ['project 5002', 'poland', 'rescue ship', '2', 'support unit'], ['project 863', 'poland', 'reconnaissance vessel', '2', 'reconnaissance group']]
there as many Type of Vessel listed as Submarine as there are Rescue Ship
there as many [ENT] of [ENT] listed as [ENT] as there are [ENT]