Year kg per hectare 1961 2001.2386105358858 1962 2216.8133663998497 1963 2057.63805016999 1964 2081.7067374436506 1965 2158.947552165547 1966 2144.719853396819 1967 2184.359663287792 1968 1892.7534997006794 1969 2034.8432429987154 1970 2291.7738641418314 1971 2191.116097334105 1972 2265.3273858807024 1973 2346.856021840969 1974 2599.229782453379 1975 2425.5092219466833 1976 2267.3225180182394 1977 2839.1412740210294 1978 2940.5399233758517 1979 3013.2887212423966 1980 3202.2228198515295 1981 3306.7843298316807 1982 3356.050493332847 1983 3256.675458480498 1984 3283.900557652885 1985 3338.0589413829093 1986 3361.581765172594 1987 3230.437162632522 1988 3165.872203791055 1989 3240.414529769465 1990 3158.010159143229 1991 3343.38421255992 1992 3430.637816940192 1993 3250.9235922039293 1994 3439.167063853575 1995 3552.64418146043 1996 3692.7562129771118 1997 3727.4677071014185 1998 3717.3459667324178 1999 3627.83401752624 2000 3620.513585863192 2001 3751.106819728145 2002 3747.254479995972 2003 3844.0342026448393 2004 3771.3180262803953 2005 3595.502170255991 2006 4121.637457786224 2007 3979.4455550071293 2008 3879.0725530034438 2009 3999.055776156157 2010 3986.3214610835994 2011 4072.668346691393 2012 4239.479163819721 2013 4593.713894567092 2014 4788.674756783535 2015 4922.457881833105 2016 4795.5952723094115 2017 5157.350755470586 2018 5270.065012112676 2019 5156.996023190506 2020 5042.030893376624 2021 5028.080519178093 2022 5387.659401665264