Year kilograms per hectare of arable land 1961 17.910083333333333 1962 21.580995850622408 1963 24.380165289256198 1964 28.304526748971192 1965 29.84426229508197 1966 35.04791547219264 1967 38.6560811916844 1968 41.44925165617077 1969 41.5822164105917 1970 45.545120457329524 1971 50.36722702790925 1972 56.78055940634429 1973 56.73076923076923 1974 58.3187036886247 1975 62.87323026851099 1976 66.10293519798357 1977 70.54306142346441 1978 74.35869123974994 1979 78.29271458705176 1980 86.28601540332387 1981 99.87734931950746 1982 91.7118575475516 1983 71.07454471873736 1984 77.96462970457304 1985 70.96875758802105 1986 66.1034126984127 1987 56.74589641434263 1988 65.62063492063493 1989 61.7207874015748 1990 61.334921875 1991 57.372093023255815 1992 55.671199574565065 1993 62.817145836436765 1994 55.9182156133829 1995 56.81481481481482 1996 58.89377289377289 1997 55.54744525547445 1998 57.13868613138686 1999 56.446220930232556 2000 53.59832030118737 2001 55.7179393496529 2002 61.20489051094891 2003 55.15007352941176 2004 60.287593984962406 2005 47.33100569259962 2006 62.33642857142857 2007 61.021746031746034 2008 56.293203125 2009 55.75039494470774 2010 53.77802601133009 2011 60.334081276489655 2012 61.583333333333336 2013 67.5 2014 66.49166666666666 2015 62.675 2016 57.25 2017 72.825 2018 90.0905175 2019 91.7907675 2020 94.2536325 2021 104.63882333333333