The U.S. and international markets for clubs offering Americanized striptease are not well defined and published revenue figures are estimates. In 2002, the size of the U.S. industry was estimated to be US$3.1 billion, spanning 2,500 clubs and generating 19% of the total gross in legal adult entertainment revenue. The U.S. market for strip clubs was estimated to be as large as US$15 billion in 2005. That same year the U.S. state of California alone accounted for US$1 billion in revenue, and the total size of the global strip club industry was estimated to be US$75 billion. Also, in 2005, an estimated 300,000 women worked as strippers in the U.S., across 3,000 clubs. An industry insider in 2008 estimated the U.S. strip club market at close to US$2 billion, basing that estimate on Adult Video News Media Network (AVN) statistics and highlighting both the methodological variances of different studies and the difficulties of providing reliable statistics on the industry. Since then, the number of clubs in the U.S. has grown to approximately 4,000 by 2010.