Three out of four uninsured Americans live in states that have yet to figure out how to deliver on its promise of affordable medical care, the Associated Press reports.

The 13 states that have adopted a plan are home to only 1 in 4 of the uninsured. An additional 17 states are making headway, but it's not clear all will succeed. The 20 states lagging behind account for 42% of the uninsured.