I'd love to provide absolutely accurate up to the second stats, but last time I went near that code to improve it, the entire internet said CM was malware, called me Hitler, and tried to kick my ass. Because of that, we switched to the Android id rather than hashed IMEI/MAC, which decreased accuracy for the sake of privacy. The theory was that over a long timeline it would smooth itself out. There is a big window of uncertainty, there is an opt-out, and there is churn. Half of these builds are unofficial versions. I think the more interesting number is the daily new user count, which has been rising steadily.
Now apparently you want to fight over accuracy this time. Good luck with that.
That said, this whole system is due for an overhaul soon.