2007, Milwaukee, Wisconsin
2004, Boston, Massachusetts
1993, Charleston, West Virginia
1993, Richmond, Virginia
1989, Aurora, Colorado
1988, Boston, Massachusetts
1987, Dallas, Texas
1987, Boston, Massachusetts
1986, Washington, District of Columbia
1984, Denver, Colorado
1984, Dallas, Texas
1984, San Antonio, Texas
1984, Washington, District of Columbia
1983, Des Moines, Iowa
1983, Houston, Texas
1983, Washington, District of Columbia
1982, Boston, Massachusetts
1982, Richmond, Virginia
1981, , Massachusetts