The average cost of a prostitute's services in the developed world has dropped from about R3617 an hour in 2006 to around R2766.
The Economist reported the price drop after analysing 190000 female sex workers' profiles. The data covered 84 cities in 12 countries, with the biggest number of workers in the US and most of the rest in big cities in rich countries.
What is driving down the price?
Even the oldest profession isn't immune to supply and demand.
The 2007-08 recession drove up unemployment, increasing the number of women participating in the trade. In addition, migration makes price control harder and casual sex is more available online.
However, prostitutes are using brothels and agencies less, thereby keeping a greater percentage of their income.