Year Measure 1971 313.12048 1972 346.88993 1973 392.29481 1974 399.50955 1975 377.36206 1976 390.78275 1977 401.47637 1978 331.1604 1979 399.6862 1980 425.93854 1981 418.43545 1982 376.65042 1983 165.61406 1984 93.49242 1985 163.80644 1986 259.30428 1987 288.61975 1988 305.03354 1989 308.84073 1990 326.76477 1991 339.77162 1992 355.21546 1993 340.51666 1994 340.90268 1995 354.82305 1996 367.6332 1997 393.38259 1998 275.16434 1999 361.0315 2000 332.01748 2001 337.76817 2002 310.92339 2003 221.1595 2004 219.85524 2005 245.84522 2006 296.74282 2007 244.09464 2008 264.26435 2009 263.01223 2010 280.51448 2011 318.48838 2012 345.7033 2013 379.67451 2014 354.71405