As of the census of 2000, there were 325,957 people, 149,937 households, and 94,460 families residing in the county.  The population density was 570 people per square mile (220/km2).  There were 182,467 housing units at an average density of 319 per square mile (123/km2).  The racial makeup of the county was 92.65% Race (United States Census), 4.18% Race (United States Census) or Race (United States Census), 0.22% Race (United States Census), 0.77% Race (United States Census), 0.03% Race (United States Census), 1.14% from Race (United States Census), and 1.02% from two or more races.  4.34% of the population were Race (United States Census) or Race (United States Census) of any race. 89.7% spoke only English language at home; 4.4% spoke Spanish language, 1.3% German language, and 1.0% French language at home.. How many more housing units are there than households?