The consumer price index (CPI), the most widely tracked benchmark for inflation, rose 8.6% on a year-over-year basis in May, topping expectations that it would decline to 8.2% from April’s 8.3%. The core CPI – which strips out food and energy costs – rose 6% year-over-year in May, dipping from April’s 6.2%, but more than expectations for 5.9%.