ShopperTrak compiles its data from retailers' sales logs, though it doesn't account for online sales. It works with more than 1,000 retailers, malls and entertainment venues.
Read MoreTeen fashion retailers are going out of style
The firm said that one of the big takeaways from 2014 is that the holidays are becoming less dependent on a single day. Although Super Saturday and Black Friday ranked as the top two sales days of the period—raking in $9.2 billion and $9.1 billion, respectively—the former only posted muted growth. Black Friday sales fell more than 7 percent on the year, ShopperTrak said.
"Consumers seem less attracted to the value-based pricing associated with the two days and are responding more to the sales and promotions available throughout the season," according to ShopperTrak. "This indicates that there is still a significant strength and resilience in the consumer."
Read MoreOnline sales top expectations
Earlier this week, comScore said that online spending from desktop computers topped its "fairly optimistic" expectations for the holidays, pulling in a total of $53.3 billion for November and December.
The National Retail Federation will release its final sales data on Wednesday. It's calling for sales growth of 4.1 percent.