WASHINGTON — The economy grew faster than expected at the end of last year, though the engine of that growth — companies replenishing stockpiles — is likely to weaken as consumers keep a lid on spending.

The 5.7 percent annual growth rate in the fourth quarter was the fastest pace since 2003. The Commerce Department report today is the strongest evidence to date that the worst recession since the 1930s ended last year, though an academic panel that dates recessions has yet to declare an end to it.

The two straight quarters of growth followed a record four quarters of decline. Still, the expansion in the fourth quarter was fueled by companies refilling depleted stockpiles, a trend that will eventually fade.

Growth exceeded expectations mainly because business spending on equipment and software jumped 13.3 percent, which was much more than forecast. It's the second quarter in a row that business spending has increased, after six quarters of decline.