New map that shows which countries have men with the biggest and smallest...'you know what'..*cough*

Left, countries with men with the biggest jank. Right, countries with men with the smallest...

Ah ah Naija men where una name for the list on the left? How can Ghanaian men upstage you guys like this? Which kind of yawa is this? lol
Meanwhile Congolese men, we hale o. Asian women, my condolences...lol

But seriously, who conducted this research and how did they reach such conclusions?