Year Measure 1971 1206.04806 1972 977.61755 1973 1077.26551 1974 1146.43676 1975 1180.41063 1976 1300.45291 1977 1379.55725 1978 1967.69169 1979 2445.59824 1980 3192.86853 1981 4081.19297 1982 4291.35651 1983 4406.54074 1984 3660.76162 1985 3487.24088 1986 3312.82322 1987 3781.04664 1988 4148.76812 1989 3990.98601 1990 3552.71429 1991 4002.95201 1992 4426.46391 1993 4471.44607 1994 4588.95434 1995 4510.41664 1996 4728.22817 1997 4422.53651 1998 4623.70447 1999 4611.61977 2000 4712.74367 2001 4715.13208 2002 5078.4989 2003 4990.77012 2004 5157.48036 2005 5126.34137 2006 5525.01843 2007 5556.71338 2008 6034.52326 2009 6250.32811 2010 6763.33688 2011 6307.89205 2012 6888.06639 2013 6417.91715 2014 6937.23068