Year	kg per hectare
1961	2181.5
1962	2225.3
1963	2115.2
1964	2243
1965	2399.3
1966	2399.8
1967	2628.8
1968	2527.1
1969	2676.1
1970	2754.7
1971	2963.1
1972	2926.8
1973	2983
1974	3157
1975	3302
1976	3206
1977	3198.7
1978	3437.5
1979	3435
1980	3521.1
1981	3686.7
1982	3585
1983	3526.6
1984	3927.2
1985	3739.3
1986	3855.4
1987	3920.1
1988	3807
1989	3702.7
1990	3944.9
1991	4366.3
1992	4707.4
1993	4850.9
1994	4675.3
1995	4667.4
1996	4948.3
1997	4747.6
1998	5078.2
1999	5047.4
2000	4993.9
2001	4821.4
2002	4959.2
2003	4307.2
2004	5444.4
2005	5361.4
2006	5316.1
2007	5174
2008	5353
2009	5086.9
2010	5322.5
2011	5677.2
2012	5315.1
2013	5264.6
2014	5717.5
2015	5402.2
2016	5599
2017	5174.8
2018	5350.8
2019	5336.2
2020	5626.5
2021	5562.8
2022	4750