Unless you work at Google and are privy to internal information, how could you possibly know that? The only reason you're hearing about this case is because the account holder is a university professor who lost a long standing Blogger site—used at his school and linked to by the NYT—and then the story made it to the front page of HN.

It's overwhelmingly likely that the vast, vast majority of people who lose access to their Google accounts never make it onto your radar.

It's an estimate, not an exact figure.