Ask HN: How to confirm that over 500,000 Android devices are activated daily?

This following is stated by Andy Rubin in his tweet (https://twitter.com/#!/arubin).

"There are now over 500,000 Android devices activated every day, and it's growing at 4.4% w/w"

Why? Furthermore, how do you go about verifying any company's data? It's either deducible from their financial paperwork or it's not.