DES MOINES, Iowa (AP) — Ethanol plants in Iowa have produced a record amount of the gasoline additive this year, narrowly topping last year’s record. The Iowa Renewable Fuels Association, an ethanol trade group, says Iowa’s 43 ethanol plants turned out 4.2 billion gallons of ethanol this year surpassing the 4.1 billion gallons produced in 2016.

The association’s executive director, Monte Shaw said in a statement Thursday that the record is largely due to several plant expansions, increased demand of exports and rising sales of higher blends of fuel like E15, which is 15 percent ethanol and 85 percent gasoline. Shaw says the industry will continue to push in 2018 to get more gas stations to install E15 pumps.

Iowa, the nation’s top corn grower, also leads the nation in corn-based ethanol production.