Year Measure 1960 5630.62981 1961 5605.11193 1962 5791.12496 1963 5966.04092 1964 6468.92626 1965 6909.89938 1966 7359.08819 1967 7630.16853 1968 8030.41843 1969 8532.9085 1970 8962.20221 1971 9300.71721 1972 9903.77623 1973 10297.94798 1974 10820.67527 1975 10436.94257 1976 11043.83876 1977 11762.48109 1978 12231.86054 1979 12384.14961 1980 12763.71325 1981 13196.82731 1982 12937.26688 1983 13409.72659 1984 14290.40542 1985 14800.05397 1986 15302.58739 1987 15736.76083 1988 16326.41755 1989 16402.57131 1990 16109.27998 1991 16104.46973 1992 16080.34644 1993 16235.99151 1994 16325.65728 1995 16503.27042 1996 16572.68325 1997 16608.55298 1998 16385.40196 1999 16625.3869 2000 16990.57839 2001 16807.14499 2002 16959.60079 2003 17191.15419 2004 17235.41178 2005 16912.47834 2006 16508.67863 2007 16683.69014 2008 16378.14227 2009 15450.87955 2010 15269.5726 2011 15642.96775 2012 15320.59425 2013 15719.70823 2014 15545.53511