Are you talking about the study that shows 31.6% of the population studied has antibodies obtained from having the disease? The link to methodology is called “Commercial lab data” and dated November 18 2021.
If That’s the one you’re talking about, yes that is certainly different number from 57%. But they’re measuring blood samples from people who go to the doctor. There are plenty of people who had Covid, recovered, have Covid antibodies, and do not go to the doctor And that is mentioned as one of the limitations of their study.
Here’s a note for anyone reading this post: the study I am talking about in this specific post studied only antibodies obtained from having the disease. It did not measure antibodies gained from a vaccine.