E-retailers netted $1.028 billion in sales on Monday.

Online sales hit a new one-day high of $1.028 billion the Monday after Thanksgiving, according to comScore Inc. data. The web measurement firm says the day, often referred to as Cyber Monday, was the first time online sales exceeded $1 billion in one day. The previous one-day high total was last Dec. 15, when online sales reached $913 million, comScore says.

The Cyber Monday sales total this year is a 15.9% increase from the $887 million recorded on the corresponding day a year ago. ComScore says a nearly 12% increase in average spending per buyer helped drive higher sales. Consumers’ average online spending on Monday hit $114.24, up from $102.19 a year ago.

The number of shoppers buying online increased slightly, to 9.0 million on Monday from 8.7 million last year, an increase of 3.4%. The company also says that the number of total transactions increased 5.6% to 17.1 million on Monday from 16.2 million last year. On Monday, the average online purchase was $60.05, up 9.5% from a year ago when it was $54.83.

The company says a high level of marketing activity partly contributed to the strong start of the holiday season. “It’s important to note that some of the early strength in consumer spending is almost certainly the result of retailers’ heavier-than-normal promotional and discounting activity at this early point in the season,” says Gian Fulgoni, comScore’s chairman.  “So, while we anticipate that there will be more billion-dollar spending days ahead as we get deeper into the season, only time will tell if consumer online spending remains at the elevated levels we’ve seen thus far.”

Where consumers shopped from also is evening out. Slightly fewer than half of all Cyber Monday dollars were spent shopping from work computers, approximately 48.9%, a decline of 4 percentage points from a year ago when sales tracked from work computers made up approximately 52.9% of total sales. Meanwhile, dollars spent shopping from home computers increased by 3.8 percentage points from about 41.6% a year ago to about 45.4% of all spending on Monday. U.S. sites accessed from computers in other countries made up the remaining 5.8%, equal the amount tracked last year. The figures exceed 100% because of comScore rounding.