ACCRA (Reuters) - Ghana's annual producer price inflation rose to 19.5 percent in April from a revised 19.2 percent year-on-year the month before, the national statistics office said on Wednesday. The figure, which is high compared with average inflation in the region, is an indication of fiscal challenges facing the West African nation's economy. Ghana began a three-year aid program worth $918 million with the International Monetary Fund in April to tackle its wide public deficit, growing public debt and high inflation.