Year Percent 1980 107.97065 1981 110.15567 1982 111.82762 1983 107.16421 1984 116.77205 1985 113.83561 1986 102.81656 1987 108.33227 1988 101.2674 1989 87.86867 1990 88.03004 1991 73.68469 1992 76.01728 1993 71.07269 1994 64.42121 1995 66.58692 1996 69.97855 1997 64.3568 1998 57.74602 1999 60.62419 2000 59.7361 2001 54.50329 2002 59.0178 2003 51.77164 2004 50.81217 2005 53.78403 2006 52.45324 2007 52.80085 2008 55.30983 2009 43.5767 2010 47.48031 2011 52.40626 2012 51.20196 2013 56.08926 2014 50.27034 2015 42.61595 2016 43.31885