Cameroon's President Paul Biya, who is 92 years old, is already the world's oldest head of state. In less than three months' time, he will seek re-election for an eighth term, which would see him reach the age of almost 100 at its end. Around 80 percent of the population was born after 1982, when he first became president, and many are calling for change. However, Biya remains the favourite as there is no united opposition. Some 81 candidates have now registered, with the full list due to be published on August 13.