Year Measure 1971 26.07966 1972 27.40517 1973 32.30046 1974 37.23553 1975 38.41133 1976 39.03613 1977 39.9709 1978 41.62854 1979 40.84795 1980 36.71659 1981 33.96482 1982 35.01394 1983 32.90725 1984 43.93431 1985 46.80043 1986 51.68548 1987 52.20537 1988 45.85255 1989 42.904 1990 49.74585 1991 47.59016 1992 47.23875 1993 44.85477 1994 45.97916 1995 45.14884 1996 45.47415 1997 42.52713 1998 41.19289 1999 60.73026 2000 62.40534 2001 52.21821 2002 60.94576 2003 64.2277 2004 64.52657 2005 75.87944 2006 84.25704 2007 90.54622 2008 98.42318 2009 112.82161 2010 131.05527 2011 141.64534 2012 156.94234 2013 158.65867 2014 190.22089