the occasion by the escort (in-call). While there may be a higher number of people involved in slavery today than at any time in history, the proportion of the population is probably the smallest in history. Share to: Answered, in, there are approximately.5 billion people in the world as of May 2017. Advertising In countries where prostitution is legal, advertising it may be legal (as in the Netherlands ) or illegal (as in India ). "10 Reasons for Not Legalizing Prostitution by Janice. Penalties for felony prostitution vary, with maximum sentences of typically 10 to 15 years in prison.