The latest reading on retail prices finds the fastest increase in more than three years. The Labor Department's Consumer Price Index rose six-tenths of one percent in May, largely because of higher food and energy costs. The core rate, excluding those volatile costs, rose a more restrained two-tenths. That gives some comfort to financial markets, which are bracing for the likelihood of an interest rate increase at the end of the this month. In today's report, the government says energy costs rose four and a-half percent last month, the biggest increase in four months.