- Maine (5.6)
- Montana and Vermont (5.0)
- Washington (4.8)
- Alaska (4.6)
- Iowa (4.5)
- Kentucky, Nevada and West Virginia (4.1)
- Michigan and Wisconsin (4.0)
- Connecticut, Indiana, Nebraska, New Mexico, Oregon and Pennsylvania (3.9)
- Hawaii and Minnesota (3.8)
- Kansas and Oklahoma (3.6)
- California, Tennessee and Wyoming (3.5)
- Louisiana (2.3)
- New York (2.5)
- Texas and Virginia (2.7)
- Delaware and Georgia (2.8)
- North Carolina (2.9)
- South Carolina (3.0)
- Maryland, Massachusetts and New Jersey (3.1)
- Arizona, Arkansas, Illinois and Ohio (3.2)
- Alabama and Missouri (3.3)
Data were not available for Colorado, Florida, Idaho,
Mississippi, New Hampshire, North Dakota, Rhode Island and South Dakota.