When Apple CEO Tim Cook repeatedly says that the iPhone 6 and then iPhone 6s are converting more Android users to iOS, many would wonder what that means and whether Apple is embellishing the numbers. “

“We recorded the highest rate on record for Android switchers last quarter at 30 percent,” Cook said earlier this week after Apple had announced it sold more than 48 million iPhones during the period.

But it turns out there’s actually one way to measure whether there’s real interest in switching to iPhone and we need to look no further than the Google Play Store for proof.

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Because of the way the Google Play Store is built – or better said, because Google made it that way, to highlight the performance of apps – each app has an estimated number of app downloads. That’s something you don’t see in the App Store for any app.

Thanks to this feature, we’ve learned that popular mobile apps including Gmail and Facebook have passed 1 billion downloads on Android devices. Assuming that each download is unique, that means there are more than 1 billion Android devices in use, something Google confirmed a bunch of times. In fact, that number is now at 1.4 billon according to Google’s most recent estimate.

Enter Move to iOS, Apple’s first Android app. The app was launched right around the iPhone 6s’ release and hardcore Android fans made sure to bomb it with crippling 1-star reviews. However, that doesn’t mean the app is not useful and that Android users don’t use it to move their data to iPhone.

The app’s specific purpose is to save your pictures, messages, contacts, bookmarks and Google data and then move it to the iPhone you just purchased. You won’t use it more than once on the same Android device. After all, you’re switching to iPhone. So that means that, no matter what reviews say, some of the savvy Android switchers will use it to move their data to iOS – unless they use their data backup systems.

That said, on October 29th, Google’s stats indicate that the Move to iOS app has been downloaded between 1 million and 5 million times (image above). As I just explained, these are likely unique installs for a one-time kind of usage. Now, I’ll note that on Wednesday afternoon the number was at between 500,000 and 1 million installs. That means, since yesterday, the number of installs moved past the 1 million mark.

Obviously, not all Android users who switch to iPhone install the app and not everyone who installs the app actually switches to the iPhone. But this is still a clear indication that plenty of people are interested in the new iPhones, and some of the ones that ditch Android for iPhone grab their data on the way out using Apple’s tool.

So yes, it appears that the iPhone is definitely stealing plenty of Android users, and Google can’t hide it.