| Residency | Year | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | |
| Total | 125 | 119 | 124 | 122 | 149 | 236 | 307 | 354 | 340 | 372 |
| U.S. Resident | 123 | 118 | 124 | 122 | 147 | 234 | 304 | 351 | 337 | 369 |
| Nonresident Alien | - | - | - | - | 1 | 1 | 2 | 2 | 2 | 2 |
| Unknown | 2 | 1 | - | - | 1 | 1 | 1 | 1 | 1 | 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 | 98.4% | 99.2% | 100.0% | 100.0% | 98.7% | 99.2% | 99.0% | 99.2% | 99.1% | 99.2% |
| Nonresident Alien | - | - | - | - | 0.7% | 0.4% | 0.7% | 0.6% | 0.6% | 0.5% |
| Unknown | 1.6% | 0.8% | - | - | 0.7% | 0.4% | 0.3% | 0.3% | 0.3% | 0.3% |