Downloads from Apple’s App Store for the iPhone, iPad and iPod touch, along with Android Market downloads, topped 1.2 billion during the last week in December, according to data from the analytics firm Flurry. The number of app loaded onto devices made the Christmas holiday window the single largest download week in iOS and Android history.

Weekly download averages for the first two weeks of December came in at about 750 million each, with 857 million downloads during the third week of the month. The final week of the month, however, saw a sharp increase compared to the first two weeks with its 1.2 billion app downloads.

App downloads top 1.2 billion in a single week

“The final week of the year, between Christmas and New Year’s Day, grew by 60 percent over the early-December baseline, historically punching through the billion download barrier for the first time ever to deliver 1.2 billion downloads,” Flurry’s Peter Fargo said.

The United States accounted for 42.3 percent of the total with 509 million downloads, followed by Chine with 99 million, The U.K. with 81 million, and Canada with 41 million.

New device activations played a role in the record breaking app download numbers. Flurry’s estimates put the total number of iOS and Android devices activated during the Christmas week at 20 million, and the company expects those numbers to continue to climb.

“Looking forward to 2012, Flurry expects breaking the one-billion-download-barrier per week will become more common-place,” Mr. Fargo said. “While iOS and Android growth continues to amaze, the market is still by all measures relatively nascent.”