U.S.A medical

So I have a question. ( don’t beat me down I’m just asking) so I’m in Australia and we have mostly free medical. I can walk into my hospital right now and know I will not be charged for anything, some things we do pay for in full but most things we can also get paid a percent back. I know in America you don’t have free medical and hospital visits can be expensive. So my question is how many people wait until the last minute to go to the hospital because they are worried about the bill at the end.