The Los Angeles Unified School District is the second largest school system in the nation--and perhaps the worst. Slightly less than half of its 75,000 employees are classroom teachers, meaning that Los Angeles spends just 35 percent of its budget on teacher pay. By comparison, the school systems in Houston, Texas, and Edmonton, in the Canadian province of Alberta, spend 49 percent and 56 percent, respectively, of their budgets on teachers. Since 1980, Los Angeles Unified's enrollment has grown by 180,000 students, but the district has added only 15 schools with a total of 20,000 seats. As a result, nearly 200,000 students must be bused to a distant campus while most attend multitrack, year-round schools that can push more students through but offer 17 fewer days of instruction. Although elementary schoolers in Los Angeles have made real gains in literacy in recent years, among high-school students, only 23 percent in reading and 34 percent in math meet or exceed the national norm on the Stanford 9. Of the district's teachers, 27 percent lack full credentials. The system has a chronic shortage of qualified principals.