In the county, the population was spread out with 25.8% under the age of 18, 4.4% from 18 to 24, 27.7% from 25 to 44, 30.0% from 45 to 64, and 12.1% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 101.40 males. For every 100 females age 18 and over, there were 99.70 males. The median income for a household in the county was $78,993, and the median income for a family was $90,032. Males had a median income of $70,063 versus $40,246 for females. The per capita income for the county was $34,646. 2.9% of the population and 1.9% of families were below the poverty line. 1.8% of those under the age of 18 and 4.7% of those 65 and older were living below the poverty line. As of the 2010 census, there were 17,950 people, 7,663 households, and 5,199 families living in the county. The population density was . There were 8,354 housing units at an average density of . The racial makeup of the county was 87.8% white, 6.0% Asian, 0.8% American Indian, 0.6% black or African American, 0.1% Pacific islander, 2.2% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 14.7% of the population. In terms of ancestry, 18.9% were German, 16.5% were English, 13.2% were Irish, and 6.5% were American. Of the 7,663 households, 31.3% had children under the age of 18 living with them, 58.1% were married couples living together, 6.4% had a female householder with no husband present, 32.2% were non-families, and 28.5% of all households were made up of individuals. The average household size was 2.33 and the average family size was 2.86. The median age was 44.3 years. The median income for a household in the county was $103,643 and the median income for a family was $118,993. Males had a median income of $93,040 versus $51,753 for females.