Mexico's annual inflation likely accelerated in May to above the official target, a Reuters poll showed on Friday, complicating the central bank's efforts to keep cutting its key rate amid a weakening economy. The median forecast from 10 analysts showed a rate of 4.39% for the year-on-year headline inflation rate for May, up from 3.93% in April. Core inflation, considered a better indicator of price trends because it strips out some especially volatile food and energy prices, likely also accelerated to 4.04%.