| Region 4 | ||||||
| Rate per 1000 of Registered Voters | ||||||
| Source: Office of the Secretary of State | ||||||
| 1996 | 1998 | 2000 | 2002 | 2004 | 2006 | |
| Ada | 661.96 | 590.24 | 602.49 | 533.95 | 626.03 | 558.76 |
| Boise | 834.08 | 877.95 | 750.67 | 616.53 | 678.89 | 622.22 |
| Elmore | 458.24 | 377.26 | 385.72 | 311.93 | 385.31 | 354.25 |
| Valley | 730.30 | 739.08 | 804.86 | 703.96 | 784.69 | 720.40 |
| * This data is reported by rate per 1000 of the population. | ||||||
| * Population 18 years and over | ||||||
| * This data is for the general elections of the reported years. | ||||||