Ken, a Japanase businessman takes a trip to New York for 2 weeks. He takes 200 yen with him. Unable to change it before he goes, he visits a buereau de change in the US. "I wan change 100 yen to dolla please clerk san" asks Ken to the clerk. "There you go, thats $80 back" Ken bows and walks out, he survives a week in New York on the $80 he had, but still had 100 yen for the last week. He returns to the buereau de change and asks to change the last 100 yen. "There you go, thats $70 for you sir" says the clerk. "What? Las' week I get 80 dolla for 100 yen, this week I get 70 dolla, why the hell that?!" fumes Ken. "Fluctuations" replies the Clerk. "Ya, well fluk you Americans too!"