Year Measure 1971 178.62384 1972 191.19309 1973 370.25533 1974 426.90099 1975 539.85821 1976 647.98439 1977 775.74375 1978 885.84009 1979 1051.10909 1980 1120.06153 1981 1085.19643 1982 1055.03477 1983 1030.24078 1984 1011.28589 1985 998.50766 1986 1048.9184 1987 1429.30037 1988 1534.44517 1989 1497.14224 1990 1576.86152 1991 1657.6836 1992 1752.95485 1993 1808.51258 1994 1820.39022 1995 1770.53095 1996 1787.76954 1997 1803.11021 1998 2097.58364 1999 2177.40711 2000 2222.65748 2001 2256.75049 2002 2773.94091 2003 2950.16767 2004 3109.15851 2005 3431.39489 2006 3795.84234 2007 3795.58224 2008 3159.38437 2009 3148.968 2010 3377.29408 2011 2863.80837 2012 2272.89668 2013 2367.18383 2014 1857.15658