Purely annecdotal, however in my country it's double digit %, but I'd imagine the actual immunity is much higher because: a) I know of quite a few families whe

Purely annecdotal, however in my country it's double digit %, but I'd imagine the actual immunity is much higher because: a) I know of quite a few families where one or two members tested positive, but others did not. If the virus spreads as easily as we think, then it's extremely unlikely that all of the family didn't have it at some point. b) Most of the people I know who have tested positive have had mild symptoms, I expect there are a lot of people who were asymptomatic or had very mild symptoms and just thought it was a cold. c) After 5 months of lockdown, most people have given up following the guidance about not meeting up privately and wearing masks inside if you do, but the case numbers haven't gone out of control. This also doesn't take into account vacinnations. We are at around 14% so far, so I wouldn't be surprised if total immunity is close to 50%.