The U.S. economy grew at a stronger-than-expected rate in the second quarter, led by brisk consumer and business spending as well as a surge in defense expenditures related to the Iraq war. The U.S. Commerce Department reported that it has revised preliminary growth estimates for the gross domestic product (GDP) from 2.4 percent to 3.1 percent for the April through June quarter.The rebound follows two straight quarters of anemic annualized economic growth rates of 1.4 percent in this year's first quarter and the final quarter of 2002. Economists said the revised economic-growth revision and other recent positive indicators mean that the GDP likely will show continued economic expansion. According to some experts, economic growth should approach 5 percent during the second half. Motivated by the tax cut and low inflation, consumers continue to keep the economy from sinking.