Paul W. Ferguson, July 1, 2011 – July 31, 2014 Robert A. Kennedy, Apr. 15, 2005 – June 30, 2011 Peter S. Hoff, Aug. 1, 1997 – Aug. 15, 2004 Frederick E. Hutchinson, April 1, 1992 – June 30, 1997 Dale W. Lick, Sept. 1, 1986 – June 30, 1991 Arthur M. Johnson, July 8,