NIGERIA'S annual inflation rose to 22.22% in April from 22.04% the previous month, as the price of food continued to rise, the National Bureau of Statistics said. Inflation has remained elevated in Africa's biggest economy, eroding savings and incomes, and prompting the central bank to hike interest rates to their highest level in nearly two decades. Food inflation, which accounts for the bulk of Nigeria's inflation basket, rose to 24.61% in April from 24.45% in March. "The rise in food inflation on a year-on-year basis was caused by increases in prices of oil and fat, bread and cereals, fish, potatoes,…