New York (CNN) The American jobs machine churned out another 2.1 million new jobs in 2019, driving the unemployment rate to the lowest level since 1969. At a 3.5 percent jobless rate, employers report difficulty finding workers to fill the 7.3 million unfilled jobs in America.

Textbook economics would suggest paychecks should be getting considerably fatter as employers chase after workers to hire and retain. So why is wage growth just muddling along?

Year-over-year wage growth reached 3.4 percent in February only to stall, ending the year a disappointing 2.9 percent.

"As would-be workers become scarcer, we would expect employers to have to work harder to attract and retain the workers they want," wrote Elise Gould Economic Policy Institute in a blog post after the December jobs report release. "Wage growth is the most important indicator to watch in 2020."

America Inc. boasts strong hiring, stocks at record highs , a bright housing market and a consumer willing to spend. But American paychecks have not kept up.

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