As of the census of 2000, there were 48,599 people, 18,210 households, and 11,617 families residing in the county. The population density was 97 people per square mile (38/km²). There were 20,116 housing units at an average density of 40 per square mile (16/km²). The racial makeup of the county was 96.95% Race (United States Census), 0.86% Race (United States Census) or Race (United States Census), 0.27% Race (United States Census), 0.41% Race (United States Census), 0.01% Race (United States Census), 0.32% from Race (United States Census), and 1.18% from two or more races. 1.16% of the population were Race (United States Census) or Race (United States Census) of any race. 17.3% were of English, 16.9% Irish, 14.2% German, 13.0% Italian and 9.9% American ancestry according to Census 2000. 96.0% spoke English and 1.4% Spanish as their first language.
Question: How many more housing units were there than households?
Answer: 1906