WASHINGTON (AP) — U.S. productivity grew at a solid 3.6% rate in the first three months of this year, the strongest quarterly gain in more than four years and a hopeful sign that a long stretch of weak productivity gains may be coming to an end.

The Labor Department says the first quarter increase in productivity was more than double the 1.3% rate of gain in the fourth quarter. Labor costs actually fell in the first quarter, dropping at an annual rate of 0.9%, indicating that tight labor markets are not creating unwanted wage and inflation pressures.

If it continues, an uptick in productivity would be good news for President Donald Trump and his goal of achieving sustained economic growth above 3%. Productivity is a key factor determining an economy’s growth potential.