Year kg per hectare 1961 1702.2591566835956 1962 1648.9688852762 1963 1730.8737202336517 1964 1763.0198204385465 1965 1997.1415381325264 1966 2132.0416255146138 1967 2167.648340286461 1968 2161.9540494628136 1969 2286.37653087507 1970 2126.7022497001844 1971 2567.784064579658 1972 2791.212712874619 1973 2820.457232349413 1974 2877.235501923196 1975 2810.4490492280197 1976 3107.4997050407214 1977 2962.2440981275486 1978 3144.387614194337 1979 2917.08140479664 1980 3076.524756442699 1981 3021.386945721198 1982 3449.9196391980527 1983 3201.139079019018 1984 3578.0361956793968 1985 3302.5376506365474 1986 3478.624321612946 1987 3356.6588627201504 1988 3446.120336405993 1989 3625.4939886604348 1990 3454.5877909744277 1991 3614.394965500657 1992 2518.9859658540345 1993 2772.994507080837 1994 2944.8572908211613 1995 3225.7967687441983 1996 2970.8651607768666 1997 3421.9971534932724 1998 3192.28311374895 1999 3288.7493476447535 2000 2662.670885740391 2001 3383.2658656478593 2002 3259.8623460521435 2003 2862.676355633544 2004 4128.801642681939 2005 3740.7450842351323 2006 3285.714928620498 2007 3009.3643364654995 2008 3911.425496881549 2009 3660.7090201965316 2010 3764.9820605101286 2011 4037.0793604077267 2012 3491.562283688203 2013 4149.561361684466 2014 4656.460742379867 2015 4255.412411117867 2016 4617.852834826324 2017 4868.755395939123 2018 4708.747909091727 2019 4843.275930307817 2020 4754.235908157566 2021 5106.540213236079 2022 4524.1033814477405