Year Measure 1971 1306.00622 1972 1234.93556 1973 2318.58508 1974 3828.50769 1975 4579.42983 1976 5802.91159 1977 6038.5872 1978 5441.90845 1979 5468.24509 1980 6958.97375 1981 6494.86468 1982 6777.96321 1983 6956.23091 1984 7791.73063 1985 7938.28838 1986 6776.78247 1987 6757.9475 1988 5460.69263 1989 6162.84183 1990 6673.06065 1991 7333.50233 1992 7664.06413 1993 7173.83434 1994 6477.4959 1995 7560.78562 1996 7423.53601 1997 7486.60099 1998 7287.25464 1999 7269.27356 2000 7155.50007 2001 6491.13981 2002 6219.63461 2003 7088.32193 2004 6388.21438 2005 6073.83653 2006 8511.87306 2007 8609.08489 2008 9341.20321 2009 7928.68161 2010 8337.15156 2011 9829.33304 2012 9581.15113 2013 7498.24508 2014 8632.32565