A day after iOS 8 was released to the public, research firm Chitika released figures that suggested iOS 8 adoption was off to a slower start than iOS 7. The firm said that one day after iOS 8 launched, only 7.3 percent of iOS devices in North America were running Apple’s latest mobile operating system. Now new figures from Apple suggest that adoption picked up serious steam over the last several days.

iClarified dug up some figures on Apple’s App Store distribution page, which suggests that 46 percent of iOS devices were running iOS 8 as of Sept. 21. The majority (49 percent) are still running iOS 7, while 5 percent of all iOS devices are running an even older version of the mobile operating system. If Chitika’s findings were correct earlier this week, that means that adoption increased about 38.7 percent in just five days. That’s pretty impressive, and it’s likely boosted by Apple’s efforts to include as many older devices as possible — even though iOS 8 has been pretty awful on the iPhone 4s and older iPads — and because it’s offered over-the-air to all devices at once.

As Apple continues to sell the iPhone 6 and iPhone 6 Plus, including in new markets, the iOS 8 adoption figure is only going to increase. Now if only more app developers could start working on fixing their apps to fit the larger iPhone 6 and iPhone 6 Plus displays.