Estimates of the number of prostitutes vary widely and are subject to controversy. A 1974 study put the number of prostitutes at 500,000 to 700,000. A 2004 estimate by Dr. Nitet Tinnakul from Chulalongkorn University gives a total of 2.8 million sex workers, including 2 million women, 20,000 adult males and 800,000 minors under the age of 18, but the figures for women and minors were considered to be grossly inflated by most observers, and to have resulted from poor research methods.[5] One estimate published in 2003 placed the trade at US$ 4.3 billion per year or about three percent of the Thai economy.[6] It has been suggested for example that there may be as many as 10,000 prostitutes on Koh Samui alone, an island resort destination not usually associated with prostitution, and that at least 10% of tourist dollars may be spent on the sex trade.[7] According to a 2001 report by the World Health Organisation: "The most reliable suggestion is that there are between 150,000 and 200,000 sex workers."[8] A recent government survey found that there were 76,000 to 77,000 adult prostitutes in registered entertainment establishments; however, NGOs believed there were between 200,000 and 300,000 prostitutes.[3]
Although centres such as Bangkok (Patpong, Nana Plaza, and Soi Cowboy), Pattaya, and Phuket (Patong) are often identified as primary tourist "prostitution" areas, with Hat Yai and other Malaysian border cities catering to Malaysians, prostitution takes place in nearly every major city and province in the country.
Chiang Mai and Koh Samui (Chaweng and Lamai) are also major centers. In Bangkok, the so-called Ratchadaphisek entertainment district, running along Ratchadaphisek Road near the Huai Khwang intersection, features several large entertainment venues which include sexual massage. Even karaoke style bars in small provincial towns have their own versions, with women, in addition to singing traditional Thai music, sometimes engaging in prostitution.[citation needed]