State supreme court justices are disproportionately White and don't reflect the diverse populations they serve, a new report has found.

According to statistics released by the Brennan Center for Justice at the New York University School of Law, only 20% of justices are people of color despite Black, Latino, Asian American, Native American and multiracial people making up 40% of the US population.

Additionally, the study found that in 18 states, all state supreme court justices were White. In 24 states, there were no Black state supreme court justices; in 40 states plus Washington, DC, there were no Latino state supreme court justices, 42 states had no Asian American state supreme court justices; and 47 states plus Washington, DC, had no Native American state supreme court justices.

Women are also underrepresented on state supreme court benches. Men, the report says, hold 58% of the seats. In six states, there is only one female supreme court justice.

The report notes recent appointments in some states that have helped increase diversity on the bench. For example, Michigan Justice Kyra Harris Bolden was appointed this year as the first Black woman to serve on the state's high court bench. And earlier this month, the Delaware Senate confirmed N. Christopher Griffiths, who will be the first Black man to sit on the state's high court.

Data also shows a lack of diversity in professional experience among state supreme court justices. The report says 82% of state high court justices were previously private practice attorneys; 67% served as judges on lower courts and 38% are former prosecutors.

Federal and state benches have a dearth of former public defenders, civil rights attorneys and legal service providers, according to the report.

Justice Ketanji Brown Jackson was the first former public defender appointed to the US Supreme Court. Brown was also the first Black woman to sit on the high court.

The report states that a long history of racial and gender discrimination and inequitable barriers to leadership positions have contributed to the lack of diversity.

Still, diversity remains critical to the high courts and democracy, the report says.

"Judicial diversity is key to ensuring the legitimacy and efficacy of our court system," the report says. "A diverse bench leads to increased public confidence in the courts and richer judicial deliberations."