The U.S. economy grew at a sluggish 1.5% pace from April through June. But consumer spending stayed strong. The Commerce Department reported Wednesday that growth in gross domestic product — the nation’s output of a goods and services — decelerated from a 2.1% pace from January through March. The second-quarter growth number was unchanged from the department’s first estimate. Still, consumer spending — which accounts for about 70% of U.S. economic activity — increased at a healthy 3.4% annual clip, up from 0.5% in the January-March period. The reason for the lackluster growth number was a surge in imports.