Year	kilograms per hectare of arable land
1973	1.9473684210526316
1974	1.6842105263157894
1975	2.6315789473684212
1976	2.6315789473684212
1977	2.6315789473684212
1978	2.6315789473684212
1979	2.263157894736842
1980	3.263157894736842
1984	1.763157894736842
1985	2.5526315789473686
1986	4.105263157894737
1987	1.8421052631578947
1997	2.3181818181818183
1998	2.590909090909091
1999	4.25
2000	2.9318181818181817
2001	5.282608695652174
2015	3.0346000000000006
2016	3.0816
2017	3.9134
2018	4.07
2019	4.0876
2020	5.6728
2021	5.373