Nigeria’s annual inflation rate rose to 29.90% in January from 28.92% a month earlier, the National Bureau of Statistics said Thursday.

The increase marks the 13th consecutive month of rising inflation in the West African country.

Food inflation, which accounts for agricultural products, increased to 35.41% in January from 33.9% in the previous month, however the overall increase in prices was largely due to a hike in electricity tariffs and energy prices, it said.

The price of diesel has more than doubled compared with a year ago, while petrol prices are around three times higher than at the end of May when the government removed a subsidy on petrol.

Prices have also been driven up by the Central Bank of Nigeria’s decision to allow a free float of the national currency against the U.S. dollar and other global currencies, which resulted in a large depreciation of the naira.

The currency’s value has fallen more than three and half times against the dollar since May.

The high cost of petrol and naira depreciation have resulted in sharp increases in the prices of food, transportation, housing, medicines, cocoa chemicals, industrial raw materials and other essential items, said a chemical dealer.