Year	kilograms per hectare of arable land
1961	1.1314522503533018
1962	1.0495103566977269
1963	1.3469537301975016
1964	1.2849531246822443
1965	1.6419507967063425
1966	1.7569639513108615
1967	2.190983456148653
1968	2.2582629479036727
1969	2.4054687573841456
1970	2.845776679804628
1971	3.254878997123664
1972	3.5700717681051355
1973	3.955791228638911
1974	4.291271435479671
1975	4.607367682622902
1976	5.0533750959020365
1977	5.172334486008883
1978	4.685105819818056
1979	4.896300828457784
1980	5.524284701679778
1981	6.084625906242735
1982	5.790996691190867
1983	5.860714301211424
1984	6.0421671025229955
1985	5.874744290894261
1986	5.729224473669105
1987	5.939293227932594
1988	6.1434374672670105
1989	5.627369328104784
1990	5.299428551875171
1991	5.461930691425499
1992	6.013863517214081
1993	5.780910400641634
1994	5.614690603093455
1995	6.488433172878299
1996	6.947428830936147
1997	7.906896104948597
1998	7.091087318785162
1999	7.313305987200394
2000	7.067097222438531
2001	6.704191930381974
2002	7.890114974411376
2003	6.626023507862864
2004	7.661828778756395
2005	6.94373839421602
2006	7.837031647914698
2007	8.06340634030289
2008	8.419581657832733
2009	8.694545704460452
2010	10.699985397115503
2011	10.31136133246805
2012	12.026508126741344
2013	10.679812738524387
2014	12.157120499240639
2015	13.248457131627415
2016	15.135238948101756
2017	16.374061511545197
2018	15.17252007556683
2019	16.374392908150963
2020	19.949986059327042
2021	17.641588392828325