Georgia is a southern state of the United States and its U.S. postal abbreviation is GA. Georgia was one of the thirteen colonies that revolted against British rule in the American Revolution. It was the thirteenth colony and became the fourth state, ratifying the United States Constitution on January 2, 1788. Georgia's population in 2000 was 8,186,453 (U.S. Census). Georgia is one of the fastest growing states in the nation, with an estimated 8,829,383 people in 2004. Georgia is also known as the Peach State or Empire State of the South . The state song, Georgia on My Mind by Hoagy Carmichael was originally written about a woman of that name, but after Georgia native Ray Charles sang it, the state legislature voted it the state song. Ray Charles sang it on the legislative floor when the bill passed. The state tree is the Southern live oak (Quercus virginiana), the state bird is the brown thrasher (Toxostoma rufum), and the state flower is the cherokee rose (Rosa laevigata). Several U.S. Navy ships have been named USS Georgia in honor of this state.