Year	kilograms per hectare of arable land
1961	5.183363336333634
1962	5.705553247061617
1963	6.465653944831785
1964	7.578797136996715
1965	8.03091350178047
1966	8.991432837070422
1967	9.967467902307172
1968	10.444891204748425
1969	10.764743234662307
1970	11.851126060251536
1971	13.473097475585037
1972	14.650245533382092
1973	15.010742339905322
1974	15.429102592338287
1975	16.175050741207
1976	16.67295262816353
1977	16.6251758267052
1978	16.92351317630156
1979	18.698570723179373
1980	21.393870256293255
1981	23.73100473142221
1982	22.94841845907971
1983	19.134065025471422
1984	19.00237091675448
1985	18.294520464189198
1986	17.379075905182376
1987	16.331298563906756
1988	18.409515964920782
1989	17.517936005583568
1990	17.553303285208127
1991	17.045348964477252
1992	16.680166009244246
1993	17.81422270571959
1994	16.915108305600626
1995	16.19354425515563
1996	18.66745767715418
1997	18.4521647617416
1998	16.75144326886358
1999	16.875973316079516
2000	16.226482543571468
2001	16.739944473762705
2002	19.227180860581914
2003	15.597627190743577
2004	16.318735740643834
2005	14.183064706408807
2006	16.4345762980706
2007	17.0376257638387
2008	17.17571845520048
2009	17.03274085852636
2010	18.38024137845689
2011	18.798235379339843
2012	18.54803900974533
2013	18.98148171674292
2014	19.90995366327051
2015	19.203219310992463
2016	21.073205452550937
2017	24.190287061763197
2018	23.67245414705789
2019	24.698915912672923
2020	29.341515591446214
2021	28.82158470270444