I think zero added sulphites wines are more common than you might think, even if they a minority of all natural wines.
If you take a look at the list of natural wines filtered by a lower SO2 content on the Raw Wine website, and then click around on several wines, you will find a fair proportion have no added sulphites. Unfortunately there is no filter for “no added sulphites” so it is difficult to get statistics from that source. Here are wines with under 20ppm SO2
Also note that the Organic Wine category in the USA is not allowed to have added sulphites.