Data on shopping trends suggest that consumers are going to make retailers work a little bit harder - and discount a little bit more - to meet December sales targets.

So far this year, according to ShopperTrak:

• Foot traffic in U.S. stores fell 6.1 percent in November over November 2008. • Sales fell 0.1 percent in November. • Sales for the week ending Dec. 5 fell 0.3 percent over last year. • Weekly sales fell 18 percent during the week of Dec. 5, signaling what experts call a "Black Friday hangover."

What does this all mean?

“Our data suggests smart consumers held off visits to various retail locations early in the month, then very economically planned trips to specific stores later in the month during Black Friday weekend to take advantage of door buster sales and other holiday promotions,” said Bill Martin, co-founder of ShopperTrak, in a release on his website.

Martin also suggests that shoppers may soon feel reduced inventories in stores as momentum picks up as expected.

But with shoppers attuned to discounts - and researching their purchases to find the cheapest deals - it may take more discounts or special promotions to keep that momentum building toward Saturday, Dec. 19.

That's the day retailers call "Super Saturday" as shoppers make their last big push for holiday gifts.