Year Percent 1995 32.53 1996 36.34 1997 34.94 1998 35.3 1999 37 2000 36.82 2001 37.16 2002 38.52 2003 38.74 2004 37.47 2005 55.34 2006 57.2 2007 56.09 2008 54.15 2009 54.47 2010 55.49