Year Measure 1960 1576.33881 1961 1627.51357 1962 1753.14389 1963 1880.99382 1964 2062.99498 1965 2163.96033 1966 2255.18842 1967 2357.58493 1968 2596.17772 1969 2830.59397 1970 3031.52105 1971 3217.04526 1972 3612.35553 1973 3941.60374 1974 4134.39088 1975 3887.47743 1976 4247.40638 1977 4404.82432 1978 4623.38968 1979 4906.08508 1980 4893.88535 1981 4910.95328 1982 4904.07001 1983 5043.97536 1984 5285.54376 1985 5502.66841 1986 5617.41982 1987 5876.963 1988 6057.06273 1989 6205.76377 1990 6380.31322 1991 6655.41438 1992 6850.66377 1993 6881.07214 1994 7176.24051 1995 7379.73708 1996 7527.68854 1997 7701.61213 1998 7913.05858 1999 7944.12981 2000 8247.67711 2001 8267.18722 2002 8311.89268 2003 8411.90066 2004 8576.2235 2005 8509.99707 2006 8683.67129 2007 8614.6795 2008 8521.49674 2009 7903.95548 2010 8393.94962 2011 8021.90927 2012 7973.22417 2013 7972.94635 2014 7709.12308