Sorry to debunk your research but after many people figured out that the percentage may not be accurate, the developer of steem.supply found a bug in the code and tried to fix it and make it more accurate. In that same update to website, the comma was removed and was possibly replaced by a decimal. I'm not sure if the dev has now implemented a regional format, where Europeans will see a comma and Americans will see a decimal point.
Here is the dev's update note:
https://steemit.com/steem/@dragosroua/steem-supply-update-removed-ads-interface-cleanup-bug-fixing