Year Measure 1960 336.9136 1961 365.84012 1962 363.16405 1963 394.93896 1964 410.25183 1965 440.88294 1966 451.75081 1967 486.58542 1968 497.129 1969 579.97249 1970 663.86151 1971 726.05046 1972 745.28395 1973 798.83518 1974 824.36122 1975 845.36244 1976 872.34937 1977 845.36895 1978 916.76939 1979 998.1607 1980 1022.46365 1981 1006.49413 1982 1119.20463 1983 1117.91313 1984 1115.89427 1985 1093.85857 1986 1208.47428 1987 1241.19567 1988 1299.58511 1989 1575.75452 1990 1680.96239 1991 1703.31644 1992 1813.88585 1993 1786.45194 1994 1827.69667 1995 2014.0205 1996 1986.83697 1997 2083.48768 1998 2240.06732 1999 2390.49473 2000 2390.09794 2001 2391.22819 2002 2477.48975 2003 2400.76592 2004 2462.98506 2005 2519.00493 2006 2390.32461 2007 2402.4264 2008 2337.27139 2009 2304.02668 2010 2222.62969 2011 2163.98211 2012 2039.0119 2013 2057.86133 2014 2034.51263 2015 2131.68189