In 2015, acne was estimated to affect 633 million people globally, making it the 8th most common disease worldwide.[9][18] Acne commonly occurs in adolescence and affects an estimated 80–90% of teenagers in the Western world.[19][20][21] Lower rates are reported in some rural societies.[21][22] Children and adults may also be affected before and after puberty.[23] Although acne becomes less common in adulthood, it persists in nearly half of affected people into their twenties and thirties and a smaller group continue to have difficulties into their forties.[8]