Complex sentence: The Census Bureau projects a U.S. population of 417 million in 2060, a 38% increase from 2007 (301.3 million), and the United Nations estmates the U.S. population will be 402 million in 2050, an increase of 32% from 2007.
Split into simpler sentences: The Census Bureau projects a U.S. population of 417 million in 2060, which is a 38% increase from 2007 (301.3 million). However, the United Nations projects a U.S. population of 402 million in 2050, an increase of 32% from 2007.