U.S. labor force growth is set to slow further over the next decade as more Americans retire, which will confine the economy to a moderate growth path, according to government report on Tuesday. In its biennial employment projections for 2014-2024, the Labor Department forecast the work-age population increasing at an annual rate of 0.5 percent, reaching 163.8 million in 2024. Labor force participation was forecast to decline to 60.9 percent in 2024 from 62.9 percent in 2014.