Retail sales rose a solid 4 percent for the 2010 holiday shopping season, marking the first uptick in two years, according to a report released Monday from ShopperTrak.

The sales gain for the combined months of November and December 2010, compared to the same period in 2009, occurred even as customer traffic remained flat, the firm said. The results suggest that consumers are making fewer visits to malls and individual stores, but spending more once they get there, said Bill Martin, co-founder of the Chicago-based customer research firm.

While overall shopping levels haven’t returned to a pre-recession pace, the 2010 holiday season “should be seen as a relatively encouraging sign for retailers heading into 2011,” Martin said.

Holiday sales were hurt the past two seasons as the recession took its toll on consumers. Retail sales fell 0.1 percent in 2009 as foot traffic tumbled 3.4 percent. In 2008, sales fell 5.7 percent, while foot traffic plummeted 15 percent.

ShopperTrak said that Black Friday — the promotional bonanza that takes place on the day after Thanksgiving — ranked as the biggest volume shopping day for the seventh year in a row.

Retailers helped boost sales this year by introducing Black Friday promotions weeks ahead of Thanksgiving. November sales rose 5.8 percent while traffic increased 4.6 percent. December sales rose 2.6 percent while traffic dropped 2.6 percent. A blizzard along the Eastern seaboard kept consumers at home on Christmas weekend.