Year Measure 1971 57.65682 1972 64.21953 1973 66.48009 1974 67.02718 1975 70.95519 1976 72.57641 1977 74.54493 1978 81.05481 1979 89.12266 1980 94.77345 1981 100.50158 1982 109.85314 1983 115.15374 1984 118.23397 1985 128.12275 1986 136.66237 1987 137.25418 1988 141.15468 1989 138.33439 1990 151.41624 1991 157.64298 1992 166.05943 1993 182.50195 1994 199.63148 1995 215.70526 1996 204.44021 1997 229.75124 1998 249.10207 1999 262.94782 2000 294.75127 2001 290.80444 2002 303.15909 2003 326.40644 2004 354.62571 2005 400.52123 2006 403.60646 2007 420.98273 2008 427.20705 2009 426.1501 2010 461.12671 2011 504.20829 2012 524.30845 2013 525.72261 2014 531.26956