What do they have in common?

Diploma’s Count, published by Editorial Projects in Education Research Center lists the states with the highest and lowest graduation rate:

Highest Graduation Rate                 Lowest Graduation Rate

New Jersey  83.3%                             Nevada                  45.4%

Iowa            82.8%                            New Mexico           54.1%

Wisconsin    80.5%                            Louisiana               54.7%

Pennsylvania 80.4%                           South Carolina       55.6%

Vermont      80.2%                             Georgia                 58.1%

What do the highest graduating states have in common?

What do the lowest graduating states have in common?