The world's oldest profession is still going strong. Very strong.

Havoscope has come out with data detailing which countries spend the most on prostitutes.

How exactly did the site figure out the numbers:

Havocscope calculates the world’s prostitution revenue by adding up the estimated market values from countries where prostitution revenue is available. The revenue estimates comes from a wide range of sources, such as public health programs, law enforcement initiatives and other criminal justice programs, as well as media reports.

It's big business. Revenue generated by paying for sex totals $186 billion around the world, which is so big it actually dwarfs the Powerball jackpot. China easily tops the list, which makes sense considering five million people work in the sex trade.

1. China: $73 billion
2. Spain:  $26.5 billion
3. Japan:  $24 billion
4. Germany:  $18 billion (Legal Industry)
5. United States:  $14.6 billion
6. South Korea:  $12 billion
7. India:  $8.4 billion
8. Thailand:  $6.4 billion
9. Philippines:  $6 billion
10. Turkey:  $4 billion

Per capita, it's a slightly different story. Here's a look at the leading nations when it comes to how much each person spends paying for sex:

1. Spain $372
2. Switzerland $291
3. South Korea $165
4. Germany $151
5. Japan $128
6. Bulgaria $122
7. Thailand $63
8. Taiwan $53
9. Ireland $45
10. Israel $42