First quarter GDP cut to 1.8 percent WASHINGTON The U.S. economy grew at an annual rate of 1.8 percent in the first three months of the year, significantly slower than first thought. The steep revision was mostly because consumers spent less than previously estimated, a sign that higher taxes could be having a deeper impact on growth. The Commerce Department revised its growth estimate for the January-March quarter down from a 2.4 percent annual rate. The revised rate was still faster than the 0.4 percent rate in the October-December quarter. Economists had thought growth in the April-June quarter would be 2 percent or less, although the revision will likely change those estimates. They had also expected growth to strengthen in the second half of this year. The Federal Reserve last week said that it would begin to slow its bond purchases later this year and end them next year if the economy continues to strengthen. The Fed's bond purchases have helped keep long-term interest rates low. The revision also may alter that plan, if growth stays weak. The latest estimate was the government's third look at first-quarter growth. The bulk of the revision was because consumer spending was cut to an annual rate of 2.6 percent. That's sharply lower than the 3.4 percent rate estimated last month. Consumer spending accounts for 70 percent of economic activity. Much of the change reflected a lower estimate for spending on services such as heat and electricity. Export growth was also trimmed as was investment spending by businesses in buildings. An increase in Social Security taxes on Jan. 1 has reduced take-home pay for most Americans. A person earning $50,000 a year has roughly $1,000 less to spend, while a high-earning couple has less than $4,500. Many economists had thought that the tax increase, along with steep government spending cuts, would start to affect consumers in the second quarter, which ends next week. But the revision suggests the tax increase may have hampered consumer spending a little earlier than thought. Economists had predicted that growth would rebound to a rate of around 2.5 percent in the July-September quarter and to more than a 3 percent rate in the final three months of the year. The Fed's latest economic projections are for growth of 2.3 percent to 2.6 percent this year. And it predicts that growth will accelerate next year to as much as 3.5 percent. The latest reports have been encouraging. U.S. factories are fielding more orders. Home sales and prices are rising, signaling a stronger housing recovery. Spending at retail businesses rose in May. And employers added 175,000 jobs last month, which almost exactly matched the average increase of the previous 12 months. Steady job growth has gradually reduced the unemployment rate to 7.6 percent from a peak of 10 percent in 2009. And it has lifted Americans' confidence in the economy to its highest point in 5 1/2 years.