 The per capita income for the county was $28,573.About 3.80% of families and 4.70% of the population were below the poverty line, including 5.60% of those under age 18 and 4.10% of those age 65 or over.Rockwall County was ranked the sixth fastest-growing county in the nation by the US Census Bureau from 2000 to 2010, adding 35,257 people (an 81.8% change).