(Reuters) – Annual inflation in Russia accelerated to 15.66% as of March 25, its highest since September 2015 and up from 14.53% a week earlier, the economy ministry said on Wednesday, as the battered rouble sent prices soaring amid unprecedented Western sanctions. Inflation in Russia has accelerated sharply in the past few weeks as the rouble’s fall to an all-time low boosted demand for a wide range of goods, from food staples to cars, on expectations that their prices will rise even higher. In February, annual inflation in Russia was at 9.15%. Weekly inflation in Russia slowed to 1.16% in th…