Year Measure 1971 741.96327 1972 760.61281 1973 747.57922 1974 797.46905 1975 813.39923 1976 894.14608 1977 997.7756 1978 1078.83856 1979 918.8194 1980 914.21955 1981 995.0382 1982 1082.68535 1983 1153.82837 1984 1156.80376 1985 1206.01224 1986 1372.27582 1987 1470.08942 1988 1650.13842 1989 1661.16387 1990 1510.63389 1991 1554.12274 1992 1831.05474 1993 1784.39349 1994 1761.47811 1995 1719.89782 1996 1621.48722 1997 1546.68161 1998 2002.5238 1999 2431.88254 2000 2039.05416 2001 2109.68038 2002 1949.17276 2003 2009.21837 2004 1872.47026 2005 1844.4904 2006 1932.90968 2007 2058.59752 2008 2006.29854 2009 2107.36634 2010 1946.64617 2011 2087.21166 2012 1994.7156 2013 1943.84544 2014 1970.48413