The American middle class is getting squeezed and it's getting worse. A new report by the Pew Research Center shows middle income households lost ground in 90% of the nation's 229 metropolitan areas between 2000 and 2015.

The report says the widening wealth gap is moving more middle class households into either higher, or lower income groups in major metro areas, leaving fewer people in the middle. But during this 15-year period, the trend has been much more downward than in the past.

Who is middle income?

The figures it takes to be classified as middle income varies by the size of the family. By Pew's definition, a household of three people would be middle class in 2014 if its annual income was between $42,000 and $125,000.

The most middle class areas

The following cities had the most middle class residents:

Wausau, WI: 67%

Janesville-Beloit, WI: 65%

Sheboygan, WI: 63%

Urban Honolulu, HI: 63%

Lebanon, PA: 63%