Online shoppers have spent $21.35 billion so far this holiday season, up approximately 14.4% from the corresponding 32-day period last year, according to new figures from comScore Inc. The web measurement firm bases its findings on spending that took place between Nov. 3 and Dec. 4.

The news of that sales bump follows comScore news earlier this week reporting consumers spent at least $1 billion with e-retailers on each of four days during the last week of November, with Cyber Monday—that is, the first workday after Thanksgiving—leading the pack with $1.46 billion in spending. The other billion-dollar days were Black Friday—also known as the first day after Thanksgiving—Tuesday, Nov. 27 and Wednesday, Nov. 28.

“While Cyber Monday was a high point for holiday e-commerce spending and Cyber Week saw several strong spending days, there was a clear softening in the growth rate during the back half of the week,” says comScore chairman Gian Fulgoni. “It is likely that, to some extent, holiday spending was pulled forward to the Thanksgiving-Black Friday period given the heightened promotional activity around that time. And some of the softening is a natural post-Cyber Monday lull. However, as the urgency to finish one’s holiday shopping increases we expect to see growth rates pick up again in the next couple of weeks before Christmas.”

Excluding travel and auctions, some 128.7 million consumers have bought online so far this holiday season, comScore estimates. That’s about 9% more than the same period in 2011. Average spending per buyer stands at $165.90, up 5% from last year. Those buyers have accounted for nearly 281.3 million transactions so far this holiday shopping season, a 13% increase from the same period last year, with spending per transaction reaching $75.90, up 1%.

“That we are seeing growth come from an increase in both the number of buyers and the average spending per buyers suggests broad-based strength in the e-commerce sector,” Fulgoni says. “It reflects not only the health of the e-commerce channel as more people buy online, but also the health of the consumer who has been willing to spend more online this year than last.”

In related news today, retailer clients of ChannelAdvisor Corp., which helps merchants sell on e-marketplaces, sold 43.7% more on Amazon.com during November compared with the same month a year ago. Sales on eBay Inc. increased 27.4% year over year, while sales on comparison shopping engines increased 3.9%.