NEW YORK -- Shoppers came out again to seriously shop last week, after taking a breather from a record spending spree over the Thanksgiving weekend, according to one measure.

Sales at stores opened at least a year rose 3.4 percent for the week ended Saturday compared with the previous week, according to the International Council of Shopping Centers-Goldman Sachs Weekly Chain Store Sales Index, released Tuesday.

That follows two consecutive weekly declines, compared with the previous weeks, as shoppers took a break after a discount-fueled spending spree over the Thanksgiving weekend, the traditional start of the holiday shopping season.

Compared with a year ago, sales for the week rose 4.6 percent.

And there's still more shopping to do. According to a poll of 1,000 shoppers conducted by ICSC and Goldman Sachs, shoppers on average completed 70 percent of their holiday buying as of Sunday, and 9 percent polled hadn't even started their holiday buying.

The weekly index is a sales proxy for 24 major stores, including Target, Costco and Macy's.

Michael Niemira, chief economist at the International Council of Shopping Centers, said he expects revenue at stores opened at least a year for his monthly tally of retailers to be up from 3.5 percent to 4.0 percent, following a revised 2.8 percent increase in November.

Overall he is predicting the measure to be up 3.5 percent for the combined November and December period, which is considered a solid increase.