As of 2014, 80 percent of students graduate high school in the United States. This is a milestone as it is the first time the US has broken 80 percent graduation rate.

Percent means out of 100? Lol. 72 is 100% and we now need 80%. 10% is 7.2x 2 (to get 20%) which is 14.4 so 72 - 14.4 = 57.6. 72 + 57.6 = 129.6 and 180% :)