USA, a proper thong country!

You are lucky. Been a long time since I have seen a whaletail in my part of the country, although they used to be fairly common. Changing fashions, highrise pants instead of lowrise. Sure lots of thongs still worn , just not exposed.
Nowadays ripped blue jeans are popular with girls, but all the tears are invariably on the legs in front, not in the seat or even upper thighs in back.