That the number of Android to iPhone switchers keeps growing is telling.

During his opening remarks for Apple's Q4, 2016 conference call, CEO Tim Cook once again identified Android switchers as a source of growth for the iPhone business. And one that's continuing to grow.

As you know, iPhone customers are the most satisfied and loyal customers in the world, and fiscal 2016 saw more customers switch from Android to iPhone than ever before. This is due to the superior customer experience we deliver with our products, and it's something no other company can match.

I've got a pet theory that if people just walk into carrier stores and want an inexpensive phone, maybe one that does Facebook or Snapchat or whatever the internet and messaging is to them, they'll leave with Android. If they're a little more cautious, and want something that eases them into modern phones, they'll leave with iPhone.

Other people want an experience they can control and a device they can tinker with. For them, Android and its numerous manufacturing partners are a deliberate choice. But when people no longer want to work for their experience, and want that experience to work for them, iPhone again becomes a deliberate choice.

It goes back to what Cook has said in the past, that Apple doesn't need to be everyone's first phone, but if they're not, Apple wants to be their second or third. In other words, instead of being everyone's jump-in point, Apple wants to be everyone's landing.

Things like consistently reliable updates that are pushed to all customers, on every carrier, in every region, all at the same time, all the time, plays into that. So does the service provided by Apple Store and AppleCare, and the ecosystem of other Apple products that becomes more valuable the more you add — see Apple Watch, Apple TV, and Apple Music.

That Cook keeps saying the number of Android-to-iPhone switchers is growing is also telling. When and if that slows down, it'll be telling. That it hasn't so far is equally telling.

Read: Here's why iMore readers switched from Samsung Galaxy phones to iPhone?