Washington ? Consumers, lured by a flurry of end of year free-financing deals on cars, boosted their spending in December by 0.9 percent, the largest increase in five months, providing a helping hand to the struggling economic recovery.

The sizable over-the-month increase came after a 0.4 percent advance in November and marked the biggest increase in consumer spending since July, the Commerce Department reported Friday. Consumer spending accounts for two-thirds of all economic activity in the United States.

Americans’ incomes, including wages, interest and government benefits, meanwhile, rose by a solid 0.4 percent in December, up from a 0.3 percent rise the month before. Income growth is important because it provides the fuel for spending in the future.

December’s spending and income figures were stronger than analysts were expecting. They were predicting spending to go up by 0.7 percent and incomes to grow by just 0.2 percent.

Even with the good news in December, consumers — the main force keeping the economy going — got tired in the fourth quarter as a whole. That was a major factor in the economy growing at only a 0.7 percent annual rate in the final three months of 2002, the government reported Thursday.

In the fourth quarter, consumers increased their spending at only a 1 percent rate, the worst showing since the first quarter of 1993 and down from a brisk 4.2 percent growth rate in 2002’s third quarter.

Worries about a possible war with Iraq, a sluggish job market and a turbulent stock market were factors in the fourth-quarter slowdown.