Read this article and answer this question As of the census of 2000, there were 218,590 people, 79,667 households, and 60,387 families residing in the county.  The population density was 496 people per square mile (192/km²). There were 83,146 housing units at an average density of 189 per square mile (73/km²). The racial makeup of the county was 86.77% Race (United States Census), 9.27% Race (United States Census), 0.23% Race (United States Census), 1.52% Race (United States Census), 0.06% Race (United States Census), 0.69% from Race (United States Census), and 1.47% from two or more races.  1.91% of the population were Race (United States Census) or Race (United States Census) of any race. 22.5% were of German people, 13.1% Irish people, 9.8% Italian people, 9.2% English, 8.1% "American" and 6.0% Polish ancestry.
How many more housing units are there than households?
3479