In 2000, the city the population had 23.9% under the age of 18, 8.7% from 18 to 24, 29.5% from 25 to 44, 20.5% from 45 to 64, and 17.4% who were 65 years of age or older.
The median income for a household in Sunbury was $25,893 in 2000, and the median income for a family was $33,148.