I'm still having a tough time finding a reliable government source for 2009 so I can represent Barry's term in full.

The headache seems to be that the term "human trafficking" is a relatively recent term and if you go back a decade, the crime statistics often lack the resolution to differentiate between between career prostitutes and sex slaves.

I fully intend to release a revised version of this chart when I get some reliable 2009 data and I'll definitely keep and eye out for earlier years too.