Data and statistics tell a story...
(Some of this is taken from using Census Data for Grant Writing / Tim Sarko)
"The American Community Survey (ACS) is a nationwide survey designed to provide communities a fresh look at how they are changing. It is a critical element in the Census Bureau's reengineered decennial census program. The ACS collects and produces population and housing information every year instead of every ten years." Note: ACS data is on the American FactFinder site. Tutorial