Year	kg per hectare
1961	1275.2
1962	1350.8
1963	1386.1
1964	1454.2
1965	1259.1
1966	1301.4
1967	1421.7
1968	1528.8
1969	1607.8
1970	1807.4
1971	1904.5
1972	2012.2
1973	2105.9
1974	2389.8
1975	2379.2
1976	2276.8
1977	2249.6
1978	2390.1
1979	2463
1980	2414.5
1981	2479.7
1982	2441
1983	2514
1984	2579.9
1985	2662.6
1986	2495.1
1987	2724.1
1988	2514.4
1989	2486.9
1990	2475.4
1991	2450.7
1992	2550
1993	2505.5
1994	2506.1
1995	2643.9
1996	2683.9
1997	2906.7
1998	3060.4
1999	3151.7
2000	3234.2
2001	3138.3
2002	3340.5
2003	3621.8
2004	3584.5
2005	3643.3
2006	3358.8
2007	3599.2
2008	3664.2
2009	3611.3
2010	3410.4
2011	3351.5
2012	3381.8
2013	3277.8
2014	3754.6
2015	3893.5
2016	3792.5
2017	3856
2018	4014.2
2019	4167
2020	4398.6
2021	4280.2
2022	4341.6