Might be true in Detroit or something. Usually there's a qualifier, like 40% of non-owner-occupied housing is unoccupied, and in the area that's 1% of houses or something.

(As a baseline, rentals are assumed to be unoccupied 10-20% of the time - so the total number of dwelling units in an area would be (number of owner occupied) + (number of remaining families) + (10% of remaining families) or so).