The Corvette vessel type was born in the Age of Sail. Modern Corvettes are typically dimensionally smaller than Frigates and larger than Coastal Patrol Craft though the differences between Frigates and Corvettes is beginning to lessen (some navies of the world consider vessels Corvettes when they would technically fall in line with the definition of a Frigate). Corvettes supply a balanced mix of firepower, ocean-going characteristics and rotary-wing support while presenting reasonable procurement costs. Not every major naval power emphasizes the Corvette class of surface warship - with many present in the smaller navies of the world.
For the purposes of the GFP final ranking, landlocked nations are not penalized for the lack of a standing naval force. However, nations with a standing navy are penalized for lack of certain naval assets.
Corvette strength data through 2013.
Sources: CIA.gov, CIA World Factbook, wikipedia.com, public domain print and media sources and user contributions. Some values may be estimated when official sources are lacking.