That's according to advertising and Web analytics firm Chitika, which on Thursday said that iOS 7 can now be found on 18 percent of all iOS devices less than 24 hours since it was released. By comparison, iOS 6 was installed on a lesser 14.8 percent of devices by this time last year.
"For some competitive comparison, Google reports that as of September 4, 2013, adoption of Jelly Bean, which was released in July 2012, comprises about 45 percent of the Android ecosystem," Chitika said in its findings. "Judging by past trends, it's likely that iOS 7 will surpass that mark very soon."
Chitika said its data came from a sample of around 300 million online ad impressions in North America, and was cross-referenced with Web usage worldwide. That means those metrics weren't recording ads served in other countries outside of the US and Canada.
The new numbers are conservative when compared with those from two other third-party tracking companies. According to a live tracker by San Francisco-based analytics company Mixpanel, 35.46 percent of all iOS users are now on iOS 7, a number that sat at 2.53 percent before the software was publicly released. Likewise, app marketing company Fisku reports iOS 7 usage at 24.9 percent of all active users it's tracking.
Apple in June noted thatamong its 600 million iOS devices, something the company is touting to developers as one of the advantages of building software for its platform. Last week the company said it's on track to sell its 700 millionth iOS device sometime next month.
iOS 7 went out Wednesday as a free download to users on Apple's newer devices. That includes the iPhone 4 and later, iPad 2 and later (including the iPad Mini), as well as fifth-generation iPod Touch. The software comes preinstalled on Apple's new iPhones, which go on sale Friday.