Year Measure 1960 794.81604 1961 890.68835 1962 1007.04835 1963 1119.72317 1964 1221.73081 1965 1316.46285 1966 1431.07449 1967 1551.51917 1968 1698.42756 1969 1832.49992 1970 2026.21747 1971 1949.14872 1972 2050.73788 1973 2175.58755 1974 2212.20669 1975 2106.07875 1976 2264.05719 1977 2204.17981 1978 2247.56552 1979 2340.04204 1980 2318.4273 1981 2265.93109 1982 2206.54273 1983 2203.86419 1984 2253.71892 1985 2284.8113 1986 2311.54807 1987 2407.25635 1988 2462.79678 1989 2566.10892 1990 2583.88808 1991 2645.67324 1992 2627.34001 1993 2611.99044 1994 2578.46598 1995 2799.37576 1996 2796.15474 1997 2834.40295 1998 2912.94737 1999 2957.31149 2000 3012.195 2001 3020.62119 2002 3037.26696 2003 3168.52902 2004 3169.93264 2005 3214.67412 2006 3175.79987 2007 3149.57655 2008 3087.56633 2009 2869.92071 2010 2930.58852 2011 2828.40489 2012 2709.29773 2013 2579.47254 2014 2414.484 2015 2481.75465