Many U.S. households find themselves in a fragile position financially, even in an economy with an unemployment rate near a 50-year low, according to a Federal Reserve survey.

The Fed’s 2018 report on the economic well-being of households, published Thursday, indicated “most measures” of well-being and financial resilience “were similar to, or slightly better than, those in 2017.” The slight improvement coincided with a decline in the average unemployment rate to 3.9% last year, from 4.3% in 2017.

Despite the uptick, however, the results of the 2018 survey indicated that almost 40% of Americans would still struggle in the face of a $400 financial emergency. The statistic, which was a bit better than in the 2017 report, has become a favorite rejoinder to President Trump’s boasts about a strong economy from Democratic politicians, including 2020 presidential candidate Sen. Kamala Harris of California.