Year Measure 1971 80.26251 1972 88.51511 1973 101.40204 1974 123.35541 1975 127.43282 1976 55.56261 1977 53.99098 1978 52.41073 1979 54.62001 1980 56.66357 1981 54.73521 1982 56.35475 1983 59.1045 1984 48.84541 1985 56.93257 1986 55.3061 1987 54.10817 1988 53.06598 1989 51.91407 1990 51.76051 1991 53.13282 1992 52.20404 1993 50.73213 1994 49.41732 1995 48.14635 1996 50.12844 1997 68.32801 1998 72.62493 1999 71.5371 2000 75.05661 2001 82.43409 2002 85.75827 2003 95.4219 2004 87.03619 2005 108.63038 2006 143.91188 2007 132.68128 2008 171.87958 2009 188.96167 2010 206.34058 2011 207.03126 2012 219.35636 2013 280.40252 2014 312.47602