 23.7% of residents were under the age of 18; 4.1% were between the ages of 18 and 24; 17.5% were from 25 to 44; 38% were from 45 to 64; and 16.4% were 65 years of age or older.The gender makeup of the city was 48.3% male and 51.7% female.As of the census of 2000, there were 20,308 people, 7,979 households, and 5,784 families residing in the city.