MasterCard Advisors’ report on retail sales found a 3.6% increase over the prior year in the 2009 holiday shopping season–November 1 through December 24–paced by a 15.5% increase in online sales. In 2008, retail sales in the same period declined 5.5% to 8%, according to MasterCard Advisors’ SpendingPulse, which excludes car and gasoline sales, but includes “aggregate sales activity in the MasterCard payments network, coupled with survey-based estimates for certain other payment forms, such as cash and check,” according to a company description of the report.

The release accompanying the report pointed out that while six out of ten sectors showed positive sales growth in the period, there was one additional shopping day in the season this year, which could “decrease the season’s year over-year-growth statistics by anywhere from 2% to 4%.”

However, Michael McNamara of SpendingPulse said in a prepared statement that “we have seen increasing stability in spending, as opposed to the free-fall of 2008,” which McNamara characterized last year as “one of the most challenging holiday shopping seasons in decades.”

Further reports on holiday retail sales are due out on December 29, including the International Council of Shopping Centers-Goldman Sachs store sales index, and the Johnson Redbook Index.