| Area of Residence | Rate | Cases | Map Range |
|---|---|---|---|
| Winnebago | 418.4 | 503 | 1 |
| Jefferson | 441.0 | 657 | 1 |
| Taylor | 457.2 | 352 | 1 |
| Davis | 462.6 | 388 | 1 |
| Cass | 468.5 | 765 | 1 |
| Howard | 472.4 | 495 | 1 |
| Worth | 472.7 | 394 | 1 |
| Winneshiek | 476.6 | 933 | 1 |
| Bremer | 480.0 | 1,092 | 1 |
| Marion | 480.6 | 1,437 | 1 |
| Shelby | 482.1 | 690 | 1 |
| Mitchell | 485.3 | 604 | 1 |
| Butler | 487.8 | 822 | 1 |
| Union | 488.3 | 629 | 1 |
| Story | 489.3 | 2,598 | 1 |
| Decatur | 490.6 | 416 | 1 |
| Mahaska | 490.7 | 1,025 | 1 |
| Keokuk | 491.1 | 592 | 2 |
| Ringgold | 491.5 | 325 | 2 |
| Adair | 491.6 | 446 | 2 |
| Boone | 492.2 | 1,231 | 2 |
| Poweshiek | 492.5 | 936 | 2 |
| Hamilton | 493.6 | 807 | 2 |
| Henry | 497.6 | 916 | 2 |
| Emmet | 497.6 | 566 | 2 |
| Jackson | 497.9 | 1,017 | 2 |
| Humboldt | 500.5 | 572 | 2 |
| Kossuth | 500.5 | 925 | 2 |
| Adams | 502.4 | 253 | 2 |
| Warren | 502.6 | 1,737 | 2 |
| Delaware | 504.2 | 842 | 2 |
| Greene | 504.6 | 583 | 2 |
| Clayton | 504.8 | 967 | 2 |
| Polk | 505.3 | 15,046 | 2 |
| Louisa | 506.5 | 539 | 3 |
| Floyd | 507.4 | 905 | 3 |
| Clarke | 507.8 | 452 | 3 |
| Franklin | 508.2 | 598 | 3 |
| Hardin | 509.0 | 1,028 | 3 |
| Fayette | 511.2 | 1,181 | 3 |
| Van Buren | 511.6 | 424 | 3 |
| Chickasaw | 511.9 | 673 | 3 |
| Lucas | 512.8 | 515 | 3 |
| Crawford | 513.3 | 851 | 3 |
| Webster | 513.5 | 1,950 | 3 |
| Appanoose | 513.5 | 770 | 3 |
| Madison | 515.3 | 666 | 3 |
| Carroll | 516.0 | 1,146 | 3 |
| Buena Vista | 516.2 | 967 | 3 |
| Jones | 516.5 | 998 | 3 |
| Calhoun | 517.3 | 671 | 3 |
| Dubuque | 517.3 | 4,208 | 3 |
| Monona | 518.4 | 622 | 4 |
| Benton | 520.9 | 1,218 | 4 |
| Lee | 520.9 | 1,926 | 4 |
| Pocahontas | 523.1 | 533 | 4 |
| Jasper | 523.2 | 1,870 | 4 |
| Washington | 524.0 | 1,091 | 4 |
| Buchanan | 525.9 | 994 | 4 |
| Pottawattamie | 526.3 | 4,016 | 4 |
| Guthrie | 526.5 | 653 | 4 |
| Wright | 526.7 | 826 | 4 |
| Lyon | 527.0 | 614 | 4 |
| Cherokee | 527.1 | 765 | 4 |
| Marshall | 528.8 | 2,035 | 4 |
| Mills | 529.4 | 666 | 4 |
| Sioux | 530.1 | 1,469 | 4 |
| Fremont | 531.4 | 446 | 5 |
| Montgomery | 531.8 | 661 | 5 |
| Woodbury | 531.9 | 4,483 | 5 |
| Allamakee | 533.5 | 816 | 5 |
| Linn | 533.7 | 8,590 | 5 |
| Dickinson | 533.7 | 1,028 | 5 |
| Johnson | 534.5 | 3,691 | 5 |
| Osceola | 535.0 | 384 | 5 |
| Black Hawk | 535.2 | 5,855 | 5 |
| Sac | 537.6 | 701 | 5 |
| Audubon | 538.7 | 430 | 5 |
| Ida | 538.7 | 476 | 5 |
| Muscatine | 539.2 | 1,888 | 5 |
| O'Brien | 539.3 | 916 | 5 |
| Tama | 541.5 | 1,009 | 5 |
| Plymouth | 541.5 | 1,259 | 5 |
| Cerro Gordo | 543.9 | 2,494 | 6 |
| Monroe | 544.4 | 455 | 6 |
| Clinton | 544.8 | 2,588 | 6 |
| Clay | 547.2 | 976 | 6 |
| Des Moines | 550.2 | 2,278 | 6 |
| Cedar | 550.9 | 971 | 6 |
| Harrison | 552.8 | 858 | 6 |
| Dallas | 554.1 | 1,829 | 6 |
| Grundy | 554.2 | 733 | 6 |
| Wapello | 556.6 | 1,982 | 6 |
| Hancock | 557.1 | 684 | 6 |
| Scott | 557.9 | 7,224 | 6 |
| Wayne | 559.1 | 449 | 6 |
| Palo Alto | 563.9 | 622 | 6 |
| Iowa | 565.3 | 873 | 6 |
| Page | 586.0 | 1,060 | 6 |
| Total | 520.8 | 138,110 | - |
| Rate (Areas) | |
| 418.4 - 490.7 (17) | |
| 490.8 - 505.3 (17) | |
| 505.4 - 517.3 (18) | |
| 517.4 - 530.1 (15) | |
| 530.2 - 541.5 (16) | |
| 541.6 - 586.0 (16) |