Year % of output 1971 9.16518213649487 1972 10.032109451347202 1973 10.785314250155569 1974 10.496340401496788 1975 11.690266237069697 1976 12.286689419795222 1977 12.203348147627663 1978 11.167447532250819 1979 13.003816690577375 1980 14.438953092291875 1981 14.870981014518309 1982 15.281311846197342 1983 15.345776477911606 1984 15.384615384615385 1985 15.947481704692208 1986 15.970386907204649 1987 15.472994406232834 1988 15.487766908745991 1989 15.59567349947549 1990 17.70002615630339 1991 18.236581495869125 1992 18.578875315922495 1993 17.787524879682383 1994 19.51365235641663 1995 19.737289262548206 1996 20.702617015823595 1997 20.747921287948312 1998 20.741933232116992 1999 20.914655614896134 2000 21.489688372130217 2001 21.617789064697877 2002 20.991836587909518 2003 20.54054054054054 2004 20.47526592655283 2005 22.185805167347638 2006 21.819380951520518 2007 22.487186451887194 2008 24.880869700792314 2009 25.96328661075597 2010 21.535639727956564 2011 21.292574002475078 2012 24.126543955834276 2013 25.01705636397306 2014 32.23692929368082