Year	kilograms per hectare of arable land
1964	2.475464509422114
1965	2.7363239426321124
1966	3.2104599970411636
1967	4.090617461636699
1968	4.603011553027438
1969	5.156938902459377
1970	5.442696210312063
1971	6.406636846462974
1972	7.183562977309904
1973	7.292480970480551
1974	7.463293249279722
1975	8.736064659977703
1976	9.715056653215337
1977	10.8326853014003
1978	11.768447068678872
1979	13.281712999375696
1980	14.506497864948638
1981	15.263383882075138
1982	16.281101982606074
1983	17.321319608972576
1984	17.753928617754376
1985	18.86498341273057
1986	20.779311992045944
1987	20.307362083791638
1988	21.361312378929433
1989	22.24895987285349
1990	22.465658630407127
1991	22.874945718952134
1992	27.26673630049765
1993	26.520120387057776
1994	26.78988499495669
1995	28.087722992262556
1996	27.31675617267576
1997	30.50929385570151
1998	28.982513652742348
1999	31.10524839781197
2000	31.169747929045506
2001	30.504345293494566
2002	31.63529860810723
2003	29.597428455754592
2004	31.141387534384872
2005	32.91060364883407
2006	34.178885231915
2007	32.400446738168945
2008	32.69141782869694
2009	34.57818831984699
2010	36.01633068479927
2011	36.55575399688278
2012	35.46179289801724
2013	36.78961678105304
2014	38.81288304917981
2015	38.88066864522532
2016	41.24331451456884
2017	45.51175082201439
2018	44.85737893475051
2019	47.391187021381015
2020	50.789552974288476
2021	49.72707905829045