The adoption of iOS 8 has been slower than with previous operating systems since the update became available for Apple devices yesterday, according to data collected by mobile monetization firm Tapjoy.

The new version of the mobile operating system debuted to a claim from Apple that it was “the biggest iOS release yet.” (VentureBeat’s review calls it “a solid upgrade.”) The advance hype about iOS 8 has been good, but Tapjoy found that the adoption rate is much slower than the adoption of iOS 7 in its first day.

Tapjoy observed its network of 200 million unique iOS consumers a month and found that the adoption rate is slower in part because the release schedule for the software and the hardware is different. Both the iPhone 6 and iPhone 6 Plus will not be available until Friday in the U.S. The download also takes up about a gigabyte of space, which could be burdensome for those who take a lot of videos or pictures.

iOS 8 adoption rate

Above: iOS 8 adoption rate

Image Credit: Tapjoy

While it took seven hours for iOS 7 to reach 10 percent adoption, iOS 8 was at 6 percent more than 18 hours after its initial availability. After 18 hours, iOS 7 was at 12 percent.

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The iPod Touch users are leading the way on adoption for iOS 8, in contrast to iPhone owners for past launches.

At the start of the day yesterday, approximately 84 percent of iPhone and iPad owners on the Tapjoy network were using iOS 7 or iOS 7.1, while only 44.6 percent of iPod touch owners had made the update to iOS 7 from an earlier version and 42 percent of iPod touch owners were still using iOS 6. Today, Tapjoy said that, approximately 18 hours after iOS 8 became available, 6.6 percent of iPhone owners are using it, compared to 7.6 percent of iPod and 3.9 percent of iPad owners.

By country, the top downloaders of iOS 8 are in South Korea, followed by the United States, Russia, Brazil, the United Kingdom, and Mexico.

iOS 8 adoption by country

Above: iOS 8 adoption by country

Image Credit: Tapjoy

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