| Residency | Year | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | |
| Total | 70 | 65 | 71 | 102 | 132 | 140 | 127 | 139 | 149 | 183 |
| U.S. Resident | 66 | 59 | 66 | 98 | 130 | 138 | 125 | 137 | 149 | 178 |
| Nonresident Alien | 2 | 4 | 4 | 3 | 1 | 1 | 2 | 2 | - | 5 |
| Unknown | 2 | 2 | 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 | 94.3% | 90.8% | 93.0% | 96.1% | 98.5% | 98.6% | 98.4% | 98.6% | 100.0% | 97.3% |
| Nonresident Alien | 2.9% | 6.2% | 5.6% | 2.9% | 0.8% | 0.7% | 1.6% | 1.4% | - | 2.7% |
| Unknown | 2.9% | 3.1% | 1.4% | 1.0% | 0.8% | 0.7% | - | - | - | - |