Just going to comment once. From my experience, where I live (relatively affluent state, with Lake Michigan shoreline), it's highly regional who knows how to s

Just going to comment once. From my experience, where I live (relatively affluent state, with Lake Michigan shoreline), it's highly regional who knows how to swim and who doesn't. People who grew up far south - not so much. Poorer folks - not so much. I always find it weird when people don't know how to swim (being where I am from, born when I was born, etc.), so I've definitely noticed there's certain segments of society who tend not to know. What I do know is lots of people don't know how to swim. Now - unrelated to my original post. I know a lot about the local river systems in our major cities. I wouldn't swim in even the bodies of water that look and smell nice (most don't). Actually, the rivers which don't look and smell nice are sometimes safer than the ones that do.