The education system of the United States is not adequately preparing a large proportion of its students for college, career-training and, ultimately, jobs that provide enough income to support a middle class standard of living. Only about one-third of students are proficient on national math and reading tests. Each year, more than 1 million students drop out before completing high school. The percentage of students in two- and four-year institutions of higher education enrolled in a remedial class can be as high as 60 percent. In addition, changes in the economy have elevated expectations for student achievement and the rigor of education standards. Because the education system has failed to attain hoped-for outcomes, some states are investigating new systems, including competency-based education.