Year Percent 1970 79.62849 1971 78.21974 1972 82.51035 1973 97.53357 1974 131.66359 1975 113.99593 1976 123.37514 1977 128.55519 1978 115.62262 1979 118.22701 1980 113.65799 1981 105.26998 1982 97.20392 1983 94.015 1984 100.83238 1985 103.68254 1986 96.44067 1987 99.58614 1988 102.35337 1989 109.64919 1990 121.58622 1991 122.32543 1992 128.09778 1993 130.2609 1994 133.96385 1995 139.66788 1996 126.93712 1997 113.16003 1998 114.74045 1999 116.80043 2000 136.23325 2001 100.48516 2002 99.66163 2003 100.42436 2004 101.56434 2005 95.0699 2006 105.11265 2007 104.54225 2008 97.82168 2009 86.00997 2010 98.9353 2011 112.31018 2012 117.79292 2013 96.39711 2014 86.77314 2015 81.81991 2016 84.65582 2017 66.38223