Year % of output 1960 9.027188484620131 1961 8.84531298566335 1962 8.585019602018441 1963 8.6481880534324 1964 8.610382319969744 1965 8.861329721066168 1966 9.249208140677903 1967 8.829332128536425 1968 8.80767809140843 1969 8.33409272291954 1970 8.624126828635058 1971 8.462180548334134 1972 8.743603485730743 1973 8.447523919860082 1974 8.354329830198362 1975 8.926030486312625 1976 9.073314459499453 1977 8.540564028686855 1978 8.928764144909149 1979 8.633416618452516 1980 8.758879353623762 1981 7.377265441643525 1982 8.135068799240516 1983 8.30366800029403 1984 6.943568918151747 1985 7.134002869999289 1986 6.625888536201958 1987 5.466642393575722 1988 5.4445759063938075 1989 9.680852940819703 1990 8.97712636647205 1991 7.03763746724661 1992 7.23281373487289 1993 7.375198062409953 1994 6.921891262464432 1995 7.002998024222637 1996 7.002577782680776 1997 6.058170153233062 1998 6.121613237099112 1999 5.916880156978545 2000 5.9677455224365605 2001 4.828127826083619 2002 6.460601133600299 2003 5.725173663184826 2004 6.395145689345601 2005 6.559869890258765 2006 6.516118482249336 2007 6.339613360939448 2008 6.00732163367469 2009 6.571756466961532 2010 6.306417687480121 2011 6.3576613700259745 2012 6.571058586439016 2013 6.29292020227128 2014 6.286488615191135