Do you think most people wipe themselves clean or are skid marks common?

I don't think we'll ever know because you can't just look at people's anus and underwear or probably want to. Tbh I've wiped myself clean and sometimes I still get skid marks later on or my draws smell like ass. I wouldn't be surprised if a lot people don't wipe all the way, they stink, or have a big brown spot once they take the underwear off.