NEW YORK (AP) -- Online shopping rose 10% from a year ago to $46.5 billion in November and December, the research firm comScore says. That was lower than expected as shoppers showed reluctance to spend freely and faced a shorter holiday season this year. The figures include sales from desktops and laptops but not mobile devices.

Online shopping has been a bright spot for retail sales, growing at a faster clip than overall spending. But the results fell short of the 14% rise that comScore had predicted.

ComScore chairman Gian Fulgoni said Tuesday that the double-digit rise was far higher than most analysts expect for holiday spending via all venues over the November and December period. It's an important time since retailers can make up to 40% of annual sales during the busy holiday period.

He said having six fewer shopping days this year compared to last year played a role.

"Consumers did not have the same opportunity to buy that they would have in a more typical holiday season," said Fulgoni. "They made up for it to some extent by spending significantly more online on the weekends, but so many fewer workdays provided a headwind for the season that ultimately proved very challenging to overcome."

The Monday after Thanksgiving Day -- known as "Cyber Monday" and falling on Dec. 2 this time -- was the biggest online shopping day of the year, with sales up 18% to $1.47 billion, comScore said. Sales on Thanksgiving Day rose 21% to $633 million, the report said.

Clothing, consumer electronics, computer hardware, toys and video game consoles and accessories were the top five fastest gaining categories bought online.

Online sales account for about 10% of overall spending.

A clearer picture of overall holiday sales will emerge next week when retailers and the Commerce Department report monthly retail spending data.