Year Measure 1971 2058.88039 1972 2131.63974 1973 2295.81102 1974 2285.59021 1975 2432.73088 1976 2594.39252 1977 2735.43912 1978 2921.29955 1979 2882.33415 1980 2932.52729 1981 2888.79709 1982 2876.73333 1983 2890.31998 1984 2856.93964 1985 2853.79483 1986 2917.17592 1987 3027.56522 1988 3033.68468 1989 2987.05906 1990 2683.1789 1991 2231.80614 1992 2052.96293 1993 2003.71568 1994 1892.68151 1995 2053.94209 1996 2109.77243 1997 1989.99418 1998 1823.45918 1999 1613.78233 2000 1614.20977 2001 1663.73929 2002 1755.13003 2003 1832.27861 2004 1803.46324 2005 1810.32726 2006 1884.54512 2007 1904.09689 2008 1928.96636 2009 1712.5261 2010 1730.08768 2011 1777.10615 2012 1741.72261 2013 1595.98939 2014 1591.66766