Fig. 2.

States contained inside the U.S. Census Bureau-designated divisions (N = 9 divisions). Only states inside the continental U.S. were used for our analysis. Notes: U.S. Census Bureau-designated divisions are grouped under four regions—described below: Region 1: NORTHEAST. Division 1: New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont), Division 2: Middle Atlantic (New Jersey, New York, Pennsylvania). Region 2: MIDWEST. Division 3: East North Central (Indiana, Illinois, Michigan, Ohio, Wisconsin), Division 4: West North Central (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota). Region 3: SOUTH. Division 5: South Atlantic (Delaware, District of Columbia, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia), Division 6: East South Central (Alabama, Kentucky, Mississippi, Tennessee), Division 7: West South Central (Arkansas, Louisiana, Oklahoma, Texas). Region 4: PACIFIC. Division 8: Mountain (Arizona, Colorado, Idaho, New Mexico, Montana, Utah, Nevada, Wyoming), and Division 9: Pacific (Alaska, California, Hawaii, Oregon, Washington). Alaska and Hawaii not included in the current analysis.