In 2022, U.S. production of aviation biofuels accounted for less than 0.1% of the total jet fuel used by major U.S. airlines. Per the U.S. Government Accountability Office, "The high price of SAF [Sustainable Aviation Fuel] relative to conventional jet fuel has been the primary factor inhibiting increased SAF production," as it "can cost anywhere from 2 to 8 times the price of conventional jet fuel." Governments mandate the use of biofuels like ethanol in automotive gas, thus raising the price of gasoline to consumers. Biofuels usually emit less air pollutants and greenhouse gases than petroleum-based fuels, but converting undeveloped land to cultivate crops for biofuels creates emissions. If this land is repeatedly used to produce biofuels, the net emissions will be less than using fossil fuels, but the breakeven point can range from 17 to 840 years.