Year	kg per hectare
1961	1153.5
1962	1177.6
1963	1242.2
1964	1179.9
1965	1530.5
1966	1442.5
1967	1476.7
1968	1585.7
1969	1573.4
1970	1436.2
1971	1837.8
1972	1870.8
1973	1388.8
1974	1575
1975	1895.6
1976	1713.1
1977	2058
1978	2291.7
1979	2293.6
1980	2924.5
1981	2276.3
1982	1742.7
1983	2401.5
1984	2323.6
1985	2323.6
1986	2253.5
1987	2256
1988	2518.3
1989	2621.8
1990	3096.8
1991	3299
1992	3169
1993	3419.3
1994	3815.4
1995	3777.6
1996	3483.3
1997	3790.7
1998	3768.9
1999	3676.8
2000	3626.2
2001	3549.6
2002	3683.4
2003	3171.4
2004	3059.4
2005	3189.1
2006	3759
2007	3538.2
2008	3814.3
2009	3790.7
2010	3199.2
2011	3418.9
2012	3621.5
2013	3283.3
2014	4497.5
2015	3831.6
2016	4026.1
2017	3731
2018	4210.1
2019	4052.4
2020	3357.1
2021	4672.8
2022	3575.2