Yikes. I guess that this phenomenon can in part be explained by the fact the the dollar is a very strong currency?

Or more likely, that it's wrongly sourced and misleadingly put.

25% is a lot. The number of prostitutes ranged from 10k to 30k in various estimates, 30k being the upper range. There is no way a country with a population of then 28 million people, saw a quarter of its GDP produced by 0.08% of the population who provided a sexual service.

I looked at the source and it doesn't say what it states here. Wikipedia sources it to: https://web.archive.org/web/20130430220310/http://koreajoong...

> Camptown prostitution and related businesses on the Korean Peninsula contributed to nearly 25 percent of the Korean GNP, according to Katharine Moon, a professor of political science at Wellesley College, in a 2002 study.

Katharine Moon references in her book Sex Among Allies: Military Prostitution in U.S.-Korea Relations the following: 'One EUSA officer estimates that the troops contributed to 25% of South Korea's GNP in the 1960s'.

Then goes on to mention merely that in 1964 the EUSA inspector general notes that "at the local community level, the business of prostitution is recognised as a source of income large enough to have an impact on the economy."

And US soldiers were paid well (relative to the Korean average wages at the time)?

Besides wages, soldiers have everything that civilians have to pay for provided to them (food, shelter, etc).

And also that "normal" economic activity would be heavily suppressed by the war.