Complex sentence: According to the Bureau of Indian Affairs in 1998, there are 5,086 enrolled members of the tribe, while according to the U.S.2000 census, 4,435 members were living on the reservation.
Split into simpler sentences: According to the Bureau of Indian Affairs in 1998, there were 5,086 enrolled members of the tribe. At the time of the U.S.2000 census, 4,435 members were living on the reservation.