42% domestics? That seems like a lot. I don't think I have counted less than 60% foreign vehicles in the Washington DC area where I live. People have practically stopped buying American in this area. I would estimate that about 80% of new vehicles sold here are imports. I don't think Detroit has had a majority market share in my area for 20 years.
The fact is large vehicles do not sell well in the mid-Atlantic or northeast - Detroit's
primarly offering. People from DC and most of the cities northeast of it (NYC, Philly, Boston) drive very similar vehicles. The vast majority of vehicles are foreign and very few pickups. Very few full-sized SUVs as well.