What's the name of the dealership? Remember that the manufacturers can't sell care directly, so there is at least one dealership near Detroit that processes all the paperwork for Ford sales to car rental companies like Hertz and Budget. The number of sales is Yuuuuge because of that.
On the other hand, you can tell when you are driving to Detroit and get to about 20-30 miles from city limits. No more Toyotas or Nissans or name your brand, just American name plates.