| Residency | Year | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | |
| Total | 85 | 78 | 88 | 88 | 81 | 86 | 89 | 80 | 71 | 58 |
| U.S. Resident | 83 | 75 | 85 | 84 | 78 | 84 | 87 | 78 | 69 | 56 |
| Nonresident Alien | 2 | 2 | 3 | 4 | 3 | 2 | 2 | 2 | 2 | 2 |
| Unknown | - | 1 | - | - | - | - | - | - | - | - |
| Total (%) | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% | 100.0% |
| U.S. Resident | 97.6% | 96.2% | 96.6% | 95.5% | 96.3% | 97.7% | 97.8% | 97.5% | 97.2% | 96.6% |
| Nonresident Alien | 2.4% | 2.6% | 3.4% | 4.5% | 3.7% | 2.3% | 2.2% | 2.5% | 2.8% | 3.4% |
| Unknown | - | 1.3% | - | - | - | - | - | - | - | - |