Year % of output 1971 9.325201652567381 1972 10.845188284518828 1973 9.20958255630469 1974 9.655172413793103 1975 9.57345971563981 1976 10.248320781599837 1977 8.697986577181208 1978 7.652132626414497 1979 9.610949936770066 1980 9.829474559822543 1981 10.716377122779623 1982 9.859829878998443 1983 10.707467119219347 1984 10.730593607305936 1985 11.528126896073502 1986 9.754420034793867 1987 10.348317743962026 1988 10.208230655495317 1989 9.968988932256858 1990 10.562296269467584 1991 10.774135697917703 1992 10.317349119058461 1993 8.15051965871276 1994 9.647779479326186 1995 8.122822571581983 1996 8.431468578170566 1997 8.653165425954134 1998 8.687202949407009 1999 8.320838747653795 2000 7.908144659658044 2001 9.200351493848856 2002 7.261519268344142 2003 7.31046391356009 2004 7.938628934119163 2005 8.105327654939218 2006 8.058122270112872 2007 6.464032138821856 2008 6.07355554651147 2009 5.913985740663369 2010 6.344579431050263 2011 6.944631421043522 2012 5.695003835826621 2013 6.067469794680108 2014 6.111201261069127