| FILE - In this Nov. 29, 2013, file photo, Best Buy employee Christopher Gervais, right, rings up a 32-inch LED TV in Dunwoody, Ga. Sales at U.S. stores dropped 3.1 percent to $42.7 billion for the week that ended on Sunday, Dec. 22, 2013, compared with the same week last year, according to ShopperTrak, which tracks data at 40,000 locations. | 
NEW YORK     (AP)
 -- After a strong start to the holiday shopping season, sales at stores
 have fallen for the third consecutive week as Americans continue to 
hold back on spending during what is traditionally the busiest buying 
period of the year.
 
Sales at U.S. stores 
dropped 3.1 percent to $42.7 billion for the week that ended on Sunday 
compared with the same week last year, according to ShopperTrak, which 
tracks data at 40,000 locations. That follows a decline of 2.9 percent 
and 0.8 percent during the first and second weeks of the month, 
respectively.
 
The numbers, which don't include
 online sales, are another challenge in what has largely been a 
disappointing holiday shopping season for stores.  The two-month period 
that begins on Nov. 1 is important for retailers because they can make 
up to 40 percent of their annual sales during that time.
 
Retailers
 started the season cautiously optimistic. But after a strong start 
through most of November - ShopperTrak said sales were up 3.4 percent 
for the month - retailers have found it increasingly hard to attract 
shoppers into stores despite big discounts and expanded hours during the
 final days.
 
"It's been a mediocre December," said Bill Martin, co-founder of ShopperTrak.
 
Karen
 McDonald,  a spokeswoman at Taubman Centers, which owns or operates 28 
malls, estimated that business for  the week that ended Sunday was 
unchanged to mid-single digit percentage growth compared with a year 
ago.
 
"I felt for sure it was going to be gangbusters. But it was just OK," McDonald said.
 
At
 the Garden State Plaza Mall in Paramus, N.J. on Saturday, Abercrombie 
& Fitch, AnnTaylor and Express had 50 percent sales, while 
Aeropostale was discounting its entire assortment up to 70 percent. 
Still, shoppers were cautious.
 
Barbara 
Jackson, 45, was one of them. She said she's capping her holiday budget 
at $1,500 - half of what 
she spent last year. That's because Jackson, an
 aide to the elderly, is earning less than last year.
 
"I am more budget conscious," Jackson said.
 
Shoppertrak
 estimates that holiday sales at stores so far are up 2 percent to 
$218.4 billion compared with the same period last year. That's below the
 2.4 percent forecast for the two-month period, but the company is 
standing by that estimate with a few days left before Christmas and a 
little over a week before the season ends.
 
The
 National Retail Federation, the nation's largest retail group, also 
said it's sticking with its forecast that sales in stores and online 
will be up 3.9 percent to $602.1 billion.
 
But 
even online sales, which had been a bright spot for much of the season, 
aren't growing at the expected pace. Online spending from home and work 
desktop computers in the U.S. from Nov. 1 through Dec. 15 was up 9 
percent from the same period last year to $37.8 billion, according to 
the most available data from comScore.
 
That's 
below the 14 percent growth that the Internet research firm is 
forecasting for the season. The company still expects online sales to 
grow at that pace for the season, but the category only accounts for 
about 11 percent of spending in the three months that include the 
holiday shopping season.
 
Final sales figures for the holiday shopping season are expected in January.