Answer based on context:

As of the 2010 United States Census, there were 1,951,269 people, 715,365 households, and 467,916 families residing in the county. The population density was . There were 840,343 housing units at an average density of . The racial makeup of the county was 60.9% white, 10.5% black or African American, 8.7% Asian, 0.7% Pacific islander, 0.7% American Indian, 13.5% from other races, and 5.1% from two or more races. Those of Hispanic or Latino origin made up 29.1% of the population. In terms of ancestry, 11.7% were Germans, 9.1% were Irish people, 7.6% were English people, 6.3% were Italians, and 2.7% were Americans.

How many more housing units are there than households?
124978