With most stores closed on Christmas Day, consumers went online in greater numbers than the same day a year ago to shop, according to new data from IBM.

Online sales on Christmas Day increased 16.4% from Christmas Day 2010, according to IBM’s Benchmark survey of 500 major online retailers. Early IBM data for Dec. 26 suggests that online sales yesterday were up 10% from a year ago. IBM did not provide dollar figures for its spending estimates.

Online traffic and sales originating from web-enabled mobile devices such as smartphones and tablet computers increased on Christmas Day compared with the same day a year ago, according to the IBM survey.

The company says 18.3% of all traffic to online retail sites came from a mobile device on Christmas Day, up from 8.4% a year ago. Of that traffic percentage, 7.0% of the traffic to retailers came from consumers using iPad tablet computers, 6.4% from iPhone users and 5.0% from smartphones operating on the Android platform. Overall, consumers using mobile devices accounted for 14.4% of the day’s sales, up from 5.3% on Christmas Day a year ago. IBM did not report the sales breakdown by device.

As of 2 p.m. Central time Dec. 26, mobile devices accounted for 18.7% of all of that day’s traffic to the retail sites included in the IBM Benchmark survey. Consumers using mobile devices accounted for 13.8% of sales. About 89 million mobile users in the U.S. own smartphones, according to a recent GfK/SapientNitro study, which says 30% of smartphone owners say they’ve used a mobile app to search for or purchase a product this holiday season.