I don't know how do you calculate the rust-free percentage.I like the enthusiasm! lol. Mine managed to survive 95 percent rust free in a scrap yard.
65,000 miles on in when I bought it. You're right, It's not perfect. A lot of the little brackets under my dash are a little rusty that I noticed because I had the dash out of it along with every interior panel. I remedy'd the slightest bit of surface rust in the rear under the carpet when I chassis saved the whole inside. But all the common rust areas that I typically see rust on these chassis and body's mine doesn't have so idk I guess I got lucky.I don't know how do you calculate the rust-free percentage.
Mine is not rust-free in dry San Diego - there's a fist-sized rust hole in the firewall, there was another one behind the right front fender that could not be seen from outside, I took repeated care of the floorpans and C-pillars meeting the rear quarters. I have not seen one D1 without rust at the bottom of alpine windows.
I do believe that a D1 has a better chance to survive the scrap yard than Michigan roads. Seeing that mountain of road salt at the empty riverfront lot near Renaissance Center made me cringe every time.