Complex sentence: According to a 1998 United Nations demographic survey, Japan is expected to have 272,000 centenarians by 2050; other sources suggest that the number could be closer to 1 million.
Split into simpler sentences: According to a 1998 United Nations demographic survey, Japan is expected to have 272,000 centenarians by 2050. However, other sources suggest that the number could be closer to 1 million.