Year % of output 1971 13.64562118126273 1972 13.594040968342643 1973 13.573883161512027 1974 13.553719008264462 1975 13.58609794628752 1976 13.663663663663664 1977 13.537117903930133 1978 13.525179856115107 1979 13.541666666666666 1980 13.636363636363635 1981 12.135922330097088 1982 14.819277108433734 1983 18.492343934040047 1984 21.149674620390453 1985 22.463054187192117 1986 20.680628272251308 1987 25.628930817610062 1988 23.00435413642961 1989 23.724320742213386 1990 19.963144963144963 1991 21.62458836443469 1992 20.64977973568282 1993 28.848167539267017 1994 19.708029197080293 1995 12.785862785862786 1996 9.526159921026652 1997 11.56852527357999 1998 11.767441860465116 1999 22.366710013003903 2000 22.127831715210355 2001 24.236983842010773 2002 16.418966737438076 2003 8.725084618277549 2004 12.01318154583583 2005 15.302390998593529 2006 26.798143851508122 2007 21.91682600382409 2008 18.842560947824104 2009 35.56211769668846 2010 19.833143723928707 2011 22.75672491655213 2012 18.75111826802648 2013 19.188688772933848 2014 17.655571635311144