While the nation's metropolitan areas are economically strong with more than 300 metros experiencing job growth in 2016 and accounting for 95% of all the U.S. job gains last year, growth continues to remain uneven, with nearly one-third of metro cities (121) still not having recovered their lost jobs from the Great Recession, according to a report released by the U.S. Conference of Mayors.

Those metros are predominantly older Midwestern communities suffering from the loss of heavy manufacturing jobs and an aging population and infrastructure.

The report forecasts that by the end of the decade nearly one in four U.S. metros (88) will have employment levels below their 2008 levels.

For some metros, the loss of jobs has been even more prolonged, with 23 cities having fewer jobs today than in 1990. A large number of metros (140 or nearly 37%) for the same period experienced annual job growth of less than 1%.

Issued during Infrastructure Week in Washington, D.C., the mayors' report also points to infrastructure spending as an economic tool that holds the promise of generating job growth across these metros. Such investment, if funneled to metro regions, can create jobs faster, relieve congestion, decrease costs to businesses and increase productivity.

"Some of the oldest infrastructure is in the Rust Belt metros, which our data show have lagged the national recovery and expansion. And while infrastructure investment is not a cure-all, it can provide cities a 'shot in the arm' to help jumpstart their local economies," says U.S. Conference of Mayors President Oklahoma City Mayor Mick Cornett.

(Read "Built in the U.S.A: Chamber Survey Urges Infrastructure Action.")

The report's findings project that over the next 30 years, the U.S. metro population will grow by 66.7 million people, almost all of the nation's total population growth. By 2047, 72 metros will have population exceeding 1 million, compared to 53 in 2016. In addition, five metros will have over 10 million people by 2047, whereas two currently meet that benchmark.

U.S. metros are already the most congested areas in the country, the mayors' report says. In fact, from 2013 to 2014, 95 of the nation's largest 100 metros saw increased traffic congestion, up from 61 from 2012 to 2013. The price tag associated with this congestion, which the report says represents the value of wasted time and fuel, is estimated at $160 billion in 2014 for U.S. urban areas, or $960 per commuter.

Since January 2009, 315 metros, 83% of all metros, gained jobs. And 12 of those metros, led by Provo, Utah, at 29% and Austin, Texas, at 27%, exceeded a 20% growth rate over the 2009-2016 period.

"We need the Administration and Congress to fulfill their pledge to put real dollars directly into the nation's metro cities, which are the engines of our national economy and have the best track record in delivering infrastructure on time and on budget," said U.S. Conference of Mayors CEO and Executive Director Tom Cochran.