 About 1.1% of families and 1.7% of the population were below the poverty line, including 1.1% of those under age 18 and 1.5% of those age 65 or over.As of the census of 2010, there were 21,213 people, 7,292 households, and 6,079 families living in the township.The population density was 1,071.4 people per square mile (414.9/km²).