Year Measure 1971 28.57132 1972 32.72954 1973 35.30169 1974 32.85038 1975 45.77618 1976 51.57434 1977 59.16763 1978 60.66943 1979 59.79721 1980 68.02274 1981 50.87268 1982 81.84797 1983 81.68656 1984 62.02626 1985 80.40587 1986 90.83123 1987 89.2492 1988 87.08652 1989 97.01182 1990 87.02636 1991 89.54599 1992 90.00059 1993 100.82547 1994 95.50496 1995 91.43474 1996 85.85524 1997 81.95717 1998 76.92522 1999 75.72464 2000 74.44912 2001 75.52798 2002 104.60359 2003 101.86968 2004 123.56565 2005 129.25772 2006 111.69303 2007 138.83631 2008 127.1788 2009 120.57472 2010 136.36169 2011 150.13162 2012 156.73297 2013 142.67648 2014 144.47992