Retailers in the US enjoyed a much-needed sales boost during last week's Black Friday (29 November) and show signs of continued e-commerce growth in today's Cyber Monday sales.

More than 172m shoppers visited stores and websites over Black Friday weekend, up from 147m last year, according to the National Retail Federation's 2008 Black Friday Weekend survey, conducted by Bigresearch.

Shoppers spent an average of US$372.57 this weekend, also up 7.2% over last year's $347.55. Total spending reached an estimated $41.0bn.

Just over half of shoppers - 50.9% - purchased clothing and accessories over the weekend.

NRF said the increases get the country's holiday season off to energetic start - after weak third quarter sales were reported by many retailers earlier this month.

"Pent-up demand on electronics and clothing, plus unparalleled bargains on this season's hottest items helped drive shopping all weekend," said NRF president and CEO Tracy Mullin.

"Holiday sales are not expected to continue at this brisk pace, but it is encouraging that Americans seem excited to go shopping again."

Friday was the busiest day of the weekend, when 73.6m people hit stores and websites.

Retailers were also buoyed by two-day sales as 56.9m people shopped on Saturday, up from 48.3m last year, and another 26.2m people planned to shop on Sunday.

Thanksgiving Day also continued to increase in popularity as the number of people who shopped on Thursday went up 48% over last year, to 16.2m.

However, research also found that people have done more shopping than they had one year ago - up to 39.3% from 36.4% - indicating that traffic and sales over the next several weeks will moderate.

"Though retailers should be encouraged by strong traffic and sales over the weekend, consumers are still being cautious," said Phil Rist, executive vice president, strategic initiatives, Bigresearch.

"Weekend shoppers indicated that they are still sticking to a budget and thinking carefully before making any holiday purchases."

NRF continues to project that holiday sales will rise 2.2% this year to $470.4bn.

Meanwhile, e-commerce researcher Comscore said Black Friday saw $534m in online spending, up 1% on the same day last year.

For the combination of Thanksgiving Day and Black Friday, online sales were up 2% relative to last year.

Comscore chairman Gian Fulgoni said: "It's probable that on Black Friday consumers responded positively to the very aggressive promotions and discounts being offered in retail stores, so it will be important to see how they respond to similarly attractive deals being offered online on Cyber Monday, the traditional kick-off to the online holiday shopping season."