The Diversity Index is a scale of 0 to 100 that represents the likelyhood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
| County | Diversity Index | |
|---|---|---|
| 1. | Adams County | 6.6 |
| 2. | Butler County | 6.7 |
| 3. | Audubon County | 6.9 |
| 4. | Grundy County | 7.3 |
| 5. | Van Buren County | 7.3 |
| 6. | Delaware County | 7.4 |
| 7. | Davis County | 7.6 |
| 8. | Mitchell County | 7.6 |
| 9. | Benton County | 8.5 |
| 10. | Howard County | 8.7 |
| 11. | Clayton County | 9.3 |
| 12. | Buchanan County | 9.4 |
| 13. | Lucas County | 9.4 |
| 14. | Keokuk County | 9.7 |
| 15. | Dickinson County | 9.7 |
| 16. | Adair County | 9.8 |
| 17. | Wayne County | 9.9 |
| 18. | Harrison County | 10.0 |
| 19. | Lyon County | 10.8 |
| 20. | Cedar County | 11.0 |
