Year Measure 1971 2292.65398 1972 2486.06609 1973 2683.10968 1974 2842.23122 1975 3035.63619 1976 3247.55135 1977 3437.79769 1978 3648.38703 1979 3772.28941 1980 3973.69079 1981 4125.35343 1982 4397.89056 1983 4582.12534 1984 4772.2946 1985 4678.28582 1986 4646.26094 1987 4838.62032 1988 4940.51849 1989 4963.17889 1990 4758.7319 1991 4361.14452 1992 3735.52545 1993 3807.69691 1994 3825.38662 1995 4211.12513 1996 4350.44326 1997 3970.13114 1998 3932.40178 1999 3613.36727 2000 3673.60687 2001 3859.09002 2002 3853.819 2003 3997.9026 2004 3971.82274 2005 4165.18039 2006 4366.91277 2007 4523.32288 2008 4674.50315 2009 4483.74714 2010 4560.41492 2011 4863.69144 2012 4761.91258 2013 4639.70632 2014 4708.92746