Year Measure 1971 945.82023 1972 1188.65545 1973 1231.2021 1974 924.7469 1975 869.18146 1976 998.44419 1977 1074.36652 1978 1123.51708 1979 1208.1981 1980 1261.51361 1981 1232.10137 1982 1247.82493 1983 1290.51388 1984 1327.2172 1985 1306.77418 1986 1460.41152 1987 1635.55393 1988 1642.21112 1989 1675.88184 1990 1780.7032 1991 1778.89722 1992 1958.80011 1993 2056.48115 1994 2298.3228 1995 1981.39432 1996 2157.54909 1997 2071.92838 1998 2174.77638 1999 2145.32045 2000 2265.41685 2001 2201.68138 2002 2193.67716 2003 2346.79935 2004 2161.6334 2005 2159.60271 2006 2207.92456 2007 2292.22666 2008 2388.58948 2009 2299.81076 2010 2195.3475 2011 2105.25277 2012 1961.78447 2013 1687.78543 2014 1712.12409