In 2017, the U.S. hemp production totaled 23,346 acres in 18 states, according to a new survey data from a prominent hemp-advocacy group.

That’s more than twice as much as hemp production in 2016, which totaled 9,649 acres growing in 15 states.

Around 1,456 farmers were issued state licenses to cultivate hemp this year, and 32 universities have started to conduct research on hemp, a slight increase from 30 in 2016.

Vote Hemp President Eric Steenstra used the report to urge Congress to make hemp farming legal nationwide. A federal expansion of hemp would facilitate hemp farmers’ access to seeds, he said.

Because the Industrial Hemp Farming Act of 2017 has not been heard yet, it is unlikely hemp production will be expanded by the end of 2017.

Steenstra also urged Congress to “grant farmers full federally legal rights to commercially cultivate hemp to supply the growing global market for hemp products.”