Twelve of the world's 50 highest-producing economies in 2018 were U.S. metropolitan areas.

That's according to a report that the U.S. Conference of Mayors released this week on metro economies. It includes figures for "gross metropolitan product," or GMP. Similar to gross domestic product, or GDP, this measure provides an estimate of the value of the goods and services that a metropolitan area produces.

The gross metropolitan product of 38 of the nation's metros exceeded $100 billion in 2018, the report says.

One of the datasets released with the report allows for comparisons between the gross metropolitan product of U.S. metros and the gross domestic product of foreign countries.

These estimates underscore the size of nation's urban economies. For example, the figures show that last year the Los Angeles metro region's economy ranked ahead of Indonesia's, and the economy in the Chicago area was more sizable than Switzerland's.

The chart below shows all of the U.S. metro areas that are within the top 100 in 2018 when comparing their GMPs to the GDPs of countries. The list includes more than just this country's biggest cities, such as the metro areas for cities like Columbus, Ohio, Sacramento, California and Milwaukee, Wisconsin. In total, 37 metro areas appear on the chart.

A full copy of the U.S. Conference of Mayors report can be found here.