Year kg per hectare 1961 1274.1707473735432 1962 1380.1757843017622 1963 1510.863280297623 1964 1598.0420204347251 1965 1683.2964411000066 1966 1765.812144385653 1967 1820.2821583517048 1968 1842.7534578666996 1969 1847.128339833407 1970 2042.2010011220182 1971 2078.461321733114 1972 2016.9154225242826 1973 2152.406949022793 1974 2239.122404315203 1975 2303.1979232955155 1976 2355.2722839105036 1977 2296.374402110692 1978 2537.308694149106 1979 2728.057722432028 1980 2695.304125246921 1981 2822.6799851768255 1982 3127.1817319697034 1983 3304.1813070570875 1984 3489.6274475688147 1985 3394.675096825936 1986 3451.9122962041597 1987 3513.0453973183216 1988 3479.6043659974716 1989 3570.981784955116 1990 3784.829060476626 1991 3757.367693036517 1992 3850.240791534567 1993 3984.2618732318074 1994 3975.250004172405 1995 4083.2392121439457 1996 4264.996311117256 1997 4216.06140860474 1998 4305.015729132451 1999 4301.37970326795 2000 4214.752134824103 2001 4260.955849776809 2002 4341.306157977372 2003 4341.826635262205 2004 4563.965378349165 2005 4619.748642437723 2006 4699.266830938837 2007 4734.234774011578 2008 4911.622627014338 2009 4866.157492793486 2010 4930.039650508853 2011 5071.0127937639445 2012 5185.911831266772 2013 5238.192959023235 2014 5270.238650605794 2015 5375.151813114183 2016 5366.534349756418 2017 5425.361776810543 2018 5455.107444613382 2019 5544.651175042566 2020 5554.557663607416 2021 5594.329809894416 2022 5623.300805674877