UPDATE 2-U.S. shoppers unexcited by last-ditch deals

(Recasts; adds data from ICSC, ShopperTrak and comScore)

By Jessica Wohl

CHICAGO, Dec 23 (Reuters) - The U.S. holiday shopping season is shaping up to be the worst in up to 40 years as steep discounts failed to rouse consumers even in the final weekend before Christmas, new data showed on Tuesday.

Several retail groups and research firms reported weak sales and store traffic during the "Super Saturday" weekend compared with the same period a year ago. A year-long recession, coupled with winter storms hitting large sections of the United States, kept many shoppers at home.

The International Council of Shopping Centers and Goldman Sachs said sales in the week ended Saturday, Dec. 20, fell 0.6 percent from a year earlier. The ICSC now expects holiday sales, which include all of November and December, to fall 1.5 percent to 2 percent.

That is down from its prior forecast for sales to fall as much as 1 percent, which already represented the worst performance since the ICSC began tracking such data in 1969.

Over the past 40 years, there has not been an annual decline in holiday sales.

ShopperTrak said store traffic on "Super Saturday" sank 17 percent from a year ago. Sales that day alone rose 0.5 percent from a year ago, but were down 6.5 percent for the week.

The results bolstered survey findings from America's Research Group and UBS. Just 38.7 percent of Americans said they went shopping during the final weekend before Christmas, the lowest turnout in at least six years and down from 41.6 percent in 2007.