Fresh research from the U.S. central bank shows the gap in income and wealth between the richest and poorest households, already at historically high levels, continues to widen, Federal Reserve Gov. Lael Brainard said Tuesday.

According to the Fed’s latest survey of consumer finances, to be released Wednesday, the share of income held by the top 1% of households reached 24% in 2015, up from 17% in 1988, Brainard said, in a speech to a conference on disparities in the labor market at the central bank’s headquarters.