Year Measure 1971 323.71774 1972 357.9978 1973 414.65008 1974 502.03036 1975 533.74055 1976 725.57626 1977 836.04605 1978 1108.7762 1979 1605.62184 1980 1961.17302 1981 2236.01408 1982 2641.09239 1983 2719.01081 1984 3036.21147 1985 3054.10939 1986 3381.71169 1987 3636.25474 1988 3735.67581 1989 3837.53585 1990 3994.83916 1991 4098.74916 1992 4373.13599 1993 4719.49495 1994 4809.43516 1995 4904.45025 1996 4942.1433 1997 5102.18206 1998 5444.19608 1999 5585.08586 2000 5637.55736 2001 5919.09571 2002 6021.46195 2003 6472.56824 2004 6326.0879 2005 6590.28195 2006 6820.48771 2007 6923.85001 2008 7188.99246 2009 7468.33673 2010 7973.51358 2011 8023.54414 2012 8522.89615 2013 8816.31724 2014 9444.21566