Year Measure 1971 1778.97266 1972 1707.323 1973 2308.84328 1974 2471.2987 1975 1998.79178 1976 1876.55513 1977 2000.93551 1978 2218.73327 1979 1917.65807 1980 1884.54919 1981 2062.49172 1982 2069.82024 1983 2074.43333 1984 1879.44184 1985 1638.26717 1986 1593.02929 1987 1470.42012 1988 1512.4221 1989 1370.22756 1990 1240.69535 1991 1247.10828 1992 1297.99557 1993 1337.62933 1994 1155.2836 1995 1234.83225 1996 1253.66115 1997 1237.65587 1998 1284.04216 1999 1219.1022 2000 1194.54368 2001 1250.66805 2002 1472.24718 2003 1686.85295 2004 1905.92763 2005 2140.7101 2006 2338.37632 2007 2526.9552 2008 2691.66649 2009 2851.20063 2010 3098.42154 2011 2411.3721 2012 2064.22069 2013 2913.54289 2014 2705.82333