The American Association of Petroleum Geologists (or AAPG) is one of the world's largest professional geological societies with over 31,000 members as of 2007. The AAPG works to advance the science of geology (especially in regard to exploration for and production of petroleum), to promote technology, and to inspire high professional conduct. AAPG was founded in 1917 and is headquartered in Tulsa, Oklahoma. Currently almost 1/3 of its members live outside the United States.