Year Measure 1971 695.95639 1972 873.03356 1973 844.47717 1974 775.46391 1975 687.98772 1976 778.16623 1977 822.86543 1978 950.34206 1979 907.52596 1980 1005.12246 1981 1129.51201 1982 1255.8101 1983 945.09022 1984 1245.23508 1985 1023.8994 1986 1678.11388 1987 1750.65387 1988 1871.37695 1989 1983.2688 1990 1961.64271 1991 1846.50057 1992 1807.05787 1993 2289.02151 1994 2056.3425 1995 1879.09459 1996 1836.66969 1997 2047.42275 1998 1792.82717 1999 1943.42558 2000 1731.70857 2001 2001.33578 2002 1851.91265 2003 2071.49846 2004 2066.58393 2005 2181.14374 2006 2055.68605 2007 2156.5558 2008 2043.5269 2009 1887.20341 2010 2012.31581 2011 1993.32882 2012 2090.39397 2013 1803.21011 2014 1781.50443