Year kg per hectare 1961 1122.8435395660233 1962 1183.5290535938027 1963 1251.7336502944395 1964 1286.3206243079908 1965 1274.3768441492846 1966 1315.4859489080825 1967 1396.9516062386244 1968 1396.651548552991 1969 1404.857603744511 1970 1520.3248551874867 1971 1559.5719650641458 1972 1531.9641531816944 1973 1582.6486170144167 1974 1637.8423886872076 1975 1730.7304961755842 1976 1732.7552412677167 1977 1761.1181839616247 1978 1874.9969030825384 1979 1903.9888979742109 1980 1944.8397390753585 1981 2048.223580617817 1982 2146.090484537928 1983 2238.472250148511 1984 2322.2366636321312 1985 2296.2620768316133 1986 2318.521128162892 1987 2333.1083126835733 1988 2399.8864121961005 1989 2470.1684489369654 1990 2558.467594645411 1991 2567.186823153202 1992 2464.066059976793 1993 2516.8828950575585 1994 2478.798898500544 1995 2523.2257708502216 1996 2632.569936067738 1997 2700.6100656106805 1998 2741.7729168819255 1999 2799.770859237036 2000 2748.85316748209 2001 2867.262371979774 2002 2850.3435973258715 2003 2877.461217054325 2004 2972.3662599919808 2005 3005.6830291252686 2006 3081.4906847690268 2007 3139.6946023926735 2008 3319.620078480148 2009 3279.909580275277 2010 3334.7878742177845 2011 3485.43084530621 2012 3502.684169823175 2013 3620.3203057973724 2014 3662.6395958853795 2015 3719.4432966324057 2016 3754.9151106742247 2017 3871.32973924569 2018 3886.5908768263043 2019 3983.2764817118004 2020 3951.8797674284588 2021 3995.0920249934507 2022 4082.7873027474284