New York (CNN Business) American retailers capitalized on last-minute shopping this weekend: All those late holiday gifts set a single-day record.

Saturday, December 21, also known as Super Saturday, was US retail's best day ever, pulling in a record $34.4 billion, according to Customer Growth Partners , a consulting and research firm. That totaled more than four times the sales from this year's Cyber Monday.

"Paced by the 'Big Four' mega-retailers — Walmart, Amazon, Costco, and Target — Super Saturday was boosted by the best traffic our team has seen in years," said Craig Johnson, president of the firm. "The spending momentum was so strong that even the long-ailing department stores had their best weekend of the season."

Customer traffic was down at most malls, but the proportion of customers who made a purchase during their visit rose, according to the firm. The firm's holiday analysis is based on weekly quantitative surveys the company conducts with retailers. Customer Growth Partners has tracked this data since 2005.

An estimated 147.8 million people intended to shop on Saturday in the United States, up from 134.3 million last year, according to an annual survey released last week by the National Retail Federation and Prosper Insights & Analytics.

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