Varies, but in well studied outbreaks seems to end up around 5-10% more or less. Early on it seemed like the rate was higher but turns out that was presymptomatic.
Honestly, just go rummage through the links in r/covid19 on reddit. Skip the comments altogether since the audience there is becoming mostly optimists. Skip r/coronavirus for the opposite reason, all the doomers congregate there. But at least in r/covid19 the moderators are very aggressive in preventing posts that are not some kind of plausible scientific source. It's useful to see the latest studies as they come out, without any editorializing. But you do need to read them critically, since most have not yet been peer reviewed.
You can also learn a lot from the occasional scientific commenters, they are quick to explain why a serosurvey showing 5% prevalence using a test with 98% specificity means the published results aren't worth much.
