A new report from Iowa’s Department of Revenue says biodiesel made from plant oil or animal fat is blended with more than 42% of all diesel sold in the Hawkeye State.

This translates into a tripling of biodiesel sales the past two years, totaling 23.3 million gallons. The figure says biodiesel interest is remarkable, considering just under 20% of retailers in the state offer a biodiesel blend.

EcoSeed.com reports Iowa has 12 biodiesel plants that produced 184 million gallons in 2012, accounting for nearly 17% of all biodiesel in the U.S., the most of any state.

The purpose of the report, says the department, is to determine the state’s progress toward replacing 25% of petroleum-based fuel with biofuels by the year 2020.

The report also outlined ethanol blended into gasoline sold in Iowa. It showed blends of 10%, 15%-20% and 85% ethanol accounted for nearly 82% of the gasoline sold in Iowa last year, down slightly from 2010.