Mostly to labor, Monson tells me, an astounding 84 percent of costs, which includes health care — and pensions, which are ballooning, and over which the district has no control. Labor costs are rising even as the number of full-time employees has declined from 22,619 in 2010 to 18,058 now. Monson says the district's administrative expenses are 3.5 percent of the budget, contrasted with 7 percent to 9 percent for other large districts nationally.