NASHVILLE, Tenn. (AP) — Historically Black land-grant universities in Tennessee and 15 other states have missed out on $12.6 billion in funding over the last three decades, according to the Biden administration.

Secretary of Education Miguel Cardona and Secretary of Agriculture Thomas Vilsack sent letters to the governors of each state asking them to increase funding, news outlets reported. The letter said the largest disparity was in Tennessee, where Tennessee State University has been underfunded by $2.1 billion dollars.

“Unacceptable funding inequities have forced many of our nation’s distinguished historically Black colleges and universities to operate with inadequate resources and delay critical investments in everything from campus infrastructure to research and development to student support services,” Cardona said in a statement Monday.

Letters were also sent to governors of Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Texas, Virginia and West Virginia.

The nation’s land-grant universities were founded in the 19th century on federal land to further agricultural instruction and research. Federal law requires states to provide an equitable distribution of state funding for all land-grant universities, but that hasn’t happened with many historically Black ones, a new analysis found.

The federal agencies used data from the National Center for Education Statistics and found the funding disparity in 16 of 18 states that house Black land grants. Delaware and Ohio provided equitable funding, the analysis found.