Cheyenne, WY – According to new census estimates, Wyoming's population has grown by more than 12,000 people since 2000. The Census Bureau says the state's population in 2004 was 506,529. However, the number of children from 5-17 year-old fell by more than 10,000 over the same period. As of the last official Census in 2000, the 5-17 age group made up nearly 26% of Wyoming's population. It now accounts for about 17%.