Year Percent 1984 44 1992 43.7 1994 43.5 1996 54.1 1998 50.6 2000 45.1 2002 43.3 2004 39.2 2005 41 2006 33.7 2008 37.5 2010 37.1 2012 36.4 2014 40.5 2016 34.8