U.S. employment costs increased 0.6% in the first quarter after a 0.8% gain in the fourth quarter, the Labor Department reported Friday. This was the smallest increase since the first quarter of 1999. The increase in the employment cost index was less than expected. Economists were forecasting a 0.9% gain in employment costs, according to a survey conducted by MarketWatch. Benefit costs rose 0.5% in the quarter, while wages and salaries rose 0.7%. Over the past year, employment costs have increased 2.8%, down from 3.1% in the fourth quarter. Wages and salary costs have increased 2.7% in the past year, while benefit costs increased 3.4%