Actually, I found a stronger number that says 90% of the corn grown in the US is GMO. And that 10% mostly goes to human consumption although some of it used for 'organic' livestock. It is easy enough to avoid GMO corn if you want to (and eat limited processed products).
In terms of corn grown in the US, here is a good summary of where it goes:
"Although U.S. corn is a highly productive crop, with typical yields between 140 and 160 bushels per acre, the resulting delivery of food by the corn system is far lower. Today’s corn crop is mainly used for biofuels (roughly 40 percent of U.S. corn is used for ethanol) and as animal feed (roughly 36 percent of U.S. corn, plus distillers grains left over from ethanol production, is fed to cattle, pigs and chickens). Much of the rest is exported. Only a tiny fraction of the national corn crop is directly used for food for Americans, much of that for high-fructose corn syrup."