Year Percent 1982 32.6092 1983 33.28105 1984 28.37795 1985 51.96685 1986 77.19588 1987 69.77922 1988 61.02516 1989 54.22965 1990 32.29885 1991 68.63881 1992 36.86079 1993 14.74339 1994 19.78619 1995 52.41298 1996 38.89044 1997 15.33591 2001 7.09981 2002 5.95153 2003 10.81643 2004 11.70833 2005 6.69022 2006 12.61887 2007 7.49481 2008 5.66242 2009 6.23557 2010 9.50753 2011 1.71633 2012 4.42114 2013 0.76205 2014 0.72112 2015 0.71906