I would guess that comparison to be very misleading. Singles presumably don't want to live in the countryside, they want to live in big cities with jobs and oth

I would guess that comparison to be very misleading. Singles presumably don't want to live in the countryside, they want to live in big cities with jobs and other people they could meet. In big cities, there tends to be little space for building, so especially little space for building 3 car garages. So I would guess most 3 car garages are built in the countryside, where there is lots of space for building. The two numbers point to completely separate issues. If singles would be willing to move to the countryside, perhaps they wouldn't have a problem to find accommodation. (A job could be a different matter).