Pulling stats from the list returned by searching for members matching @ in only their user name, as of a few minutes ago, there were 349, of which 261 appeared to have an email address* as their user name, and 186 of those have posted. There are 83 who use @ in the sense of 'at' or belonging to, or to replace the letter a or just to ornament their user name.
Getting these stats didn't need any admin access or special skills other than copy/pasting into a local spreadsheet that for privacy reasons has been discarded without saving.
* i.e. without spaces, containing only one @, with one or more . after the @ and ending in a valid TLD.