Not sure, but in the north east many of the old towns have residential and commercial very close to each other. Train lines run through town and the different stops have commercial around it with residential a short walk. Schools are spread across the community and crossing guards exist to help kids cross streets. Otherwise they use the sidewalk.

I think people have a weird perception that everywhere in America is sprawled suburbs. People have choice here. Some people want to live in towns that are walkable and some people don't. I know a lot of people that would hate it and enjoy having their subdivisions un-walkable from just about anything and like getting in their vehicle to drive places.

I know my preferences for lifestyle have changed as I've gotten older and started a family, etc. I loved big city life, small apartments, etc at one time but wouldn't want to live like that today. Now I like being in a town where I can walk places and have parks nearby and commuter trains and decent sized properties. But in the future I could see myself wanting to be more remote. It's nice to have choice.

I don't think you can get a quantity (ie ".1%") from a non-quantifiable thing like "generally walkable". I consider my town very walkable except for grocery stores, which is a pretty core aspect.