U.S. consumers spent $35.3 billion online during the holiday season, a 15-percent increase from last year.

comScore, a online metrics firm, said Wednesday that Christmas day saw a significant spike in digital content and subscription sales. Consumers loaded up on new tablets, e–readers, and music devices during the holiday season. The measurement tracked retail e-commerce spending for the first 56 days between the start of November through the Christmas.

Spending for the week ending on December 25 was $2.8 billion, an increase of 16 percent from last year.

During the 2011 holiday season comScore’s Digital Content & Subscriptions category accounted for 2.8 percent of retail e-commerce sales on an average day, but on Christmas Day the it accounted for more than 20 percent of sales.

comScore expects sales for this category of products to remain elevated throughout the entire week following Christmas Day.

“Holiday e-commerce spending has remained strong throughout the season, and we have now reached a record $35 billion in U.S. online sales for the season-to-date,” said comScore chairman Gian Fulgoni.

“We can now say with certainty that the $1.25 billion spent on Cyber Monday will rank it as the heaviest online spending day of the season for the second consecutive year, but we should also note that it was accompanied by nine other billion dollar spending days this year.”