iOS 7 adoption rate: 29% of Apple’s customers in first 16 hours

September 19, 2013, 12:23 PM UTC

Source: Mixpanel

FORTUNE — The mobile analytics firm Mixpanel has posted a cool little widget that lets you track the rate at which Apple’s (AAPL) mobile customers are switching from iOS 6 to iOS 7.

Here’s what it tells us:

  • As of 1 p.m. Eastern Wednesday, when Apple released its new operating system, the previous version was running on 93% of the iPhones, iPads and iPod touches still in use.
  • Sixteen hours later, 29.25% of those devices were running iOS 7.

So how many copies of iOS 7 is that?

According to Tim Cook, Apple will sell its 700th million iOS device next month. As of last January, roughly half of the iOS devices sold were still in use. If that ratio holds, it puts the number of downloads at roughly 100 million, or 6.3 million per hour. At 1.2 gigabytes per iPhone download (1.3GB for iPad) that’s nearly 2.2 terabytes per second.

Could that explain why by Wednesday afternoon Internet traffic was running at 112%, with hotspots in countries like the U.S. and the U.K. where iPhone adoption is highest?

See map below:

Source: Akamai via Global Nerdy

[NOTE: An earlier version of the story calculated the drain on the Internet using the wrong iOS 7 file size.]