The consumer price index in Angola climbed to 31.8 percent judged year-on-year in June; a rise of 2.6 percentage points from May’s year-on-year inflation rate of 29.2 percent, the country’s National Statistics Institute said this week.

The June number was the highest inflation rate recorded in at least five and a half years, financial news agency Bloomberg reported.

Inflation in the African nation has more than tripled year-on-year, as slumping prices for oil have cut the Government’s revenue and weakened its currency the kwanza against the U.S. dollar, the report said. Angola relies on oil for about 95 percent of its export income.

Angola’s central bank increased its key lending rate by 2 percentage points to 16 percent on June 30, taking its policy tightening since January to five percentage points, Bloomberg said.