https://covidestim.org/us https://covidestim.org/us has estimates on the percentage of people ever infected by state. I looked at MA, NY, and CA, and they all

https://covidestim.org/us https://covidestim.org/us has estimates on the percentage of people ever infected by state. I looked at MA, NY, and CA, and they all hover around 80% (with error bars). I can't find a cumulative US estimate. I have no idea how they came up with the estimate, but the site is maintained by reputable institutions, so I am inclined to believe these numbers unless proven otherwise.