As of the United States Census, 2000, there were 68,747 people, 28,169 households, and 17,746 families residing in the city. The population density was . There were 29,499 housing units at an average density of . The racial makeup of the city was 79.2% White (U.S. Census), 14.5% African American (U.S. Census), 1.1% Asian (U.S. Census), 1.9% from Race (United States Census), and 2.0% from two or more races. Hispanic (U.S. Census) or Latino (U.S. Census) people of any race were 3.2% of the population.. How many more housing units are there than families?