Year % of output 1960 3.0737704918032787 1961 2.486910994764398 1962 3.0821917808219177 1963 3.616236162361624 1964 4.037685060565275 1965 3.760913364674278 1966 4.717655468191565 1967 4.694167852062589 1968 4.708362614195362 1969 4.930555555555555 1970 5.969049373618276 1971 5.476369092273068 1972 5.409356725146199 1973 6.312769010043041 1974 8.454106280193237 1975 7.115749525616698 1976 6.295620437956205 1977 6.073943661971831 1978 5.88235294117647 1979 5.100182149362477 1980 2.7233115468409586 1981 9.615384615384617 1982 13.837638376383765 1983 13.404255319148936 1984 9.851301115241636 1985 7.7071290944123305 1986 4.081632653061225 1987 5.3633217993079585 1988 16.071428571428573 1989 14.873417721518987 1990 14.423076923076922 1991 15.549215406562054 1992 16.060606060606062 1993 14.456035767511178 1994 16.63778162911612 1995 27.92607802874743 1996 22.727272727272727 1997 24.137931034482758 1998 39.07103825136612 1999 35 2000 9.715639810426541 2001 4.728950403690888 2002 1.46011396011396 2003 1.4700609537468627 2004 1.1531638083973978 2005 3.464755077658303 2006 3.230376877302352 2007 3.5613870665417062 2008 4.292002934702861 2009 3.6802030456852792 2010 3.777089783281734 2011 4.566037735849057 2012 4.388828436706564 2013 6.5440778799351005 2014 6.299212598425196