Year % of output 1960 11.082251082251082 1961 10.446631339894019 1962 10.042735042735043 1963 9.001687816465587 1964 8.69710653955511 1965 8.604056943213225 1966 8.052129392599488 1967 7.343589743589743 1968 7.060121345835632 1969 6.580829756795422 1970 6.567080045095828 1971 6.417341342387046 1972 6.55626027719051 1973 6.045721088040706 1974 4.826074017016211 1975 5.215514872787681 1976 5.064971439391549 1977 5.020297674032012 1978 4.62303593583041 1979 4.474664297673147 1980 4.4346943658945985 1981 4.119074371505973 1982 4.291757241055167 1983 4.309626427427441 1984 3.7911958952932965 1985 4.288235391136547 1986 4.333009488842266 1987 4.277353364814849 1988 3.973079724915958 1989 4.019730749604692 1990 4.671786485009003 1991 4.743648514703123 1992 4.72393239502403 1993 4.6657760300584386 1994 4.562796558687836 1995 4.554533479626772 1996 4.366641251262184 1997 4.562151663570343 1998 4.5796067475272535 1999 4.441248268868282 2000 4.314800586715093 2001 4.23228181117397 2002 4.543576958620734 2003 4.605635626931118 2004 4.402212007474264 2005 4.266999597118735 2006 4.247144551890819 2007 4.224745208709939 2008 4.459505726384962 2009 4.523998730775603 2010 4.135645016420131 2011 4.359112540755571 2012 4.092626382695205 2013 4.484670595952112 2014 4.307817226526076