 According to the Census Bureau's 2009 American Community Survey, 76.1% of the County's households are occupied by families, (compared to 66.5% in the United States).This represents a decrease of 4.6 percentage points since 1990, when 80.7% of households in the County were families.Approximately 42.2% of Prince William County's households are family households occupied by parents with their own children under 18 years of age.