If you put a 20 mile perimeter around every point of North America that had continued human activity, what percentage of North America would be covered? Is it m

If you put a 20 mile perimeter around every point of North America that had continued human activity, what percentage of North America would be covered? Is it more than we'd expect? At a first glance, it seems like there are still vast reached of North America that remain completely untouched by humans. Nevertheless, is so sad that humans have effectively pushed animals outside of their habitats. Animals are smart enough to avoid humans, just as a deer is smart enough to avoid a wolf, but at some point the world is only so big.