The western black rhinoceros was heavily hunted in the beginning of the 20th century, but the population rose in the 1930s after preservation actions were taken. As protection efforts declined over the years, so did the number of western black rhinos. By 1980 the population was in the hundreds. No animals are known to be held in captivity, however, it was believed in 1988 that approximately 20–30 were being kept for breeding purposes. Poaching continued and by 2000 only an estimated 10 survived. In 2001, this number dwindled to only five. While it was believed that around thirty still existed in 2004, this was later found to be based upon falsified data.