Wage growth across the US was generally flat last quarter, according to a third-quarter index of wages released today by PayScale Inc., a Seattle-based provider of compensation data and software.

Nominal wages fell 0.1% over the third quarter and increased only 0.4% year over year; the slight gain followed a less-than-stellar second quarter when nominal wages declined. Real wages fell 1.8% since last year.

Blue-collar wages were hit hardest as wages fell for transportation; manufacturing and production; and installation, maintenance and repair jobs. Transportation jobs experienced the largest decline with wages falling 3.8% in one year.

On the flip side, wages for marketing and advertising jobs increased by 3.5% since last year.

“While key economic measures point to a robust economy, there is no question that these economic improvements have not translated into robust wage growth for the average worker,” said Katie Bardaro, chief economist at PayScale. “While it’s encouraging to see that wages are not continuing to drop — as the index reflected in Q2 — it is apparent the positive performance of many companies is not resulting in an increase in most employees’ pay checks.”

Wages in Austin, Texas, fell 1.4% year over year in September, the lowest annual wage growth of all the metro areas included in the analysis. San Francisco posted the largest increase in wages, up 2.7% since last year.

The PayScale Index tracks quarterly nominal changes in total cash compensation for full-time, private industry employees since 2007 (with a baseline of 2006).