WASHINGTON — Personal health care costs rose in the 12 months ending in May at the slowest rate in the last 50 years, as spending on hospital and nursing home services declined, the White House announced Monday. Personal consumption spending rose 1.1%, Alan Krueger, chairman of the White House Council of Economic Advisers, said. Hospital readmissions rates dropped from an average of 19% to 17.9% for Medicare patients since the passage of the 2010 health care law, Krueger said. A series of recent government reports and industry analyses have shown a decrease in overall health care costs.