<P> Most corn grown today is fed to livestock, especially hogs and poultry . In recent decades soybeans have grown in importance . The U.S. produces 40% of the world crop . </P> <P> By 1950, 99% of corn has been grown from hybrids . </P> <P> In 1997, the USEPA published its report on United States' ecoregions, in part based on "land use ." Its "Level III" region classification contains three contiguous "Corn Belt" regions, Western (47), Central (54), and Eastern (55), stretching from Indiana to eastern Nebraska . </P>

Why is the us cornbelt considered a formal region
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