What share of Mexico’s rising corn-import bill is the result of U.S. ethanol
expansion? As noted earlier, estimates of biofuels’ contribution to recent price increases
vary considerably. In general, they fall in a range of 20-40%, as the National Academy of
Sciences concluded in its survey. The literature suggests that U.S. ethanol is probably the
most significant contributor among global biofuels. But in recent years when U.S. ethanol
production expanded significantly (2005-11), there were also many other factors
contributing to increases in agricultural commodity prices and corn prices.