In fact, we are pretty average when it comes to hygiene. According to a Euromonitor survey done last year, Americans shower more often than the Chinese, British, and Japanese (where folks said they showered an average of five times a week), but less often than Brazilians and Colombians.
In general, women shower more often than men—except, according to one study, in Sweden. According to the same study, the most onerous beauty demands are placed on women in Russia. To clean up on stats, check out the Atlantic story.