Hawaii is the only state with 100% natural borders.

Alaska: 98.1% (34,797 km out of 35,442 km)

New Jersey: 97.6% (1,998 / 2,047)

Florida: 96.5% (8,585 / 8,896)

Louisiana: 95.9% (8,219 / 8,567)

Michigan: 94.4% (4,086 / 4,328)