Out of the four clubs in the league who replied to his email, Spurs base it on actual attendance.Attendance figures are announced by tickets sold. Every club does this.
It's interesting information, nonetheless.Pretty sure the police figures are only estimates themselves, although the actual will always be lower than the official record which is just tickets sold.
But it does seem too exact to be that much of an estimate.
Our match against Fenerbahce, for example, only had 44,779 fans at it.