Spain $26.5 Billion
Japan $24 Billion
Germany $18 Billion (Legal Industry)
United States $14.6 Billion
South Korea $12 Billion
India $8.4 Billion
Thailand $6.4 Billion
Philippines $6 Billion
Turkey $4 Billion
Switzerland $3.5 Billion
Indonesia $2.25 Billion
Taiwan $1.84 Billion
Ukraine $1.5 Billion
Bulgaria $1.3 Billion
United Kingdom $1 Billion
Netherlands $800 Million (Legal Industry)
Italy $600 Million
Cambodia $511 Million
Israel $500 Million
Ireland $326 Million
Czech Republic $200 Million
Jamaica $58 Million
Australia $27 Million
sources:
https://en.wikipedia.org/wiki/Prostitution_statistics_by_country
https://brobible.com/life/article/top-10-countries-spend-most-prostitutes/
https://metro.co.uk/2016/01/11/can-you-guess-which-country-spends-the-most-on-prostitutes-5615906/