Price-slashing failed to rescue a bleak holiday season for beleaguered retailers, as sales plunged across most categories on shrinking consumer spending, according to new data released Thursday.

Despite a flurry of last-minute shoppers lured by the deep discounts, total retail sales, excluding automobiles, fell over the year-earlier period by 5.5% in November and 8% in December through Christmas Eve, according to MasterCard Inc.'s SpendingPulse unit.

When gasoline sales are excluded, the fall in overall retail sales is more modest: a 2.5% drop in November and a 4% decline in December. A 40% drop in gasoline prices over the year-earlier period contributed to the sharp decline in total sales.

But considering individual sectors, "This will go down as the one of the worst holiday sales seasons on record," said Mary Delk, a director in the retail practice at consulting firm Deloitte LLP. "Retailers went from 'Ho-ho' to 'Uh-oh' to 'Oh-no.'"

The holiday retail-sales decline was much worse than the already-dire picture painted by industry forecasts, which had predicted sales ranging from a 1% drop to a more optimistic increase of 2.2%.