When I was brushing up on this for some work we're doing down here, the numbers we found were much higher. I'm in no position to dispute their numbers but I'm not so sure about the methodology they used for this.
The Philippines was estimated to have between 300,000 and a million women in prostitution in http://www.uri.edu/artsci/wms/hughes/mhvbt.htm
This was in 2010 for just Latin America
Latin America: Five million women victim to human trafficking
One month after the massacre of 72 undocumented migrants in the North East of Mexico, experts and activists at the second Latin American Conference on Smuggling and Trafficking of Human Beings have criticised the lack of attention and action given to the issue by governments. The conference host, David Fernández Dávalos, described human trafficking as a modern, particularly malignant and better disguised version of slavery. According to the Mexican Ministry of Public Security, 250.000 people throughout Latin America become victims of human trafficking every year, but numbers vary.
The Coalition Against Trafficking of Women And Girls in Latin America and the Caribbean estimate that five million women and girls are currently trapped in trafficking networks, with further 10 million in danger of falling victim to them. Even though most Latin American countries have established laws against trafficking, criminal prosecution of perpetrators remains a problem due to both the initial invisibility of the issue and the links to other organised crime such as drug trafficking.
http://www.asylumaid.org.uk/data/files/publications/143/WAN_October.pdf
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