The ADP Workforce Vitality Index, a measure of the total wages paid to the US private-sector workforce, rose 5.1% year over year to a level of 108.9 (third quarter 2013=100, not seasonally adjusted) in the third quarter of 2015.

The quarterly report analyzes the overall vitality of the US labor market based on data that identifies labor market trends and dynamics across multiple dimensions including employment growth, job turnover, wage growth and hours worked. Movement in the index depends on the contributions of wages and hours of workers who have remained in the same jobs from the previous quarter, the wages and hours of workers who switched jobs during the quarter, and employment changes.

The employment portion of the index rose 2.4% year over year.

“As the overall economy improves, wage growth among job holders appears to be picking up momentum based on the numbers over the first three quarters of this year,” said Ahu Yildirmaz, VP and head of the ADP Research Institute. “This may be based on companies wanting to retain top performers as job openings start to outpace the available talent pool.”

Workers under 25 posted the most robust wage growth, both among job holders and job switchers, with those age 25 to 34 also outperforming the older demographics.

Wage growth accelerated in construction and job switchers in that industry could expect boosts of 19.6%, according to the report. Home construction remained fairly steady in the third quarter and commercial construction accelerated. Growing talent shortages are driving up the wages that contractors are offering to lure experienced and skilled workers.

Despite the pressures that many manufacturers are under due to weaker demand from the energy and other commodity producing industries and from overseas, the shortage of qualified manufacturing workers is driving wages up 7.2% year-over-year for job holders and 11.3 % for job switchers.

Vitality in financial services held steady at a high level, according to the report. Wage growth exceeds the average for all workers at 4.1% year over year and labor shortages are driving wages for switchers up 12.6%.

The ADP Workforce Vitality Report was developed by the ADP Research Institute in collaboration with Moody’s Analytics.