Year	kg per hectare
1961	1535
1962	1560.2
1963	1521.2
1964	1623.1
1965	1575.6
1966	1380.2
1967	1545.7
1968	1588.4
1969	1616.1
1970	1611.2
1971	1635.1
1972	1543.3
1973	1680.1
1974	1671
1975	1742.2
1976	1799.4
1977	1845.3
1978	1992.8
1979	2197.4
1980	2600.2
1981	2766.5
1982	2989.1
1983	2874.7
1984	2890.3
1985	2896.7
1986	2863.7
1987	2885.9
1988	2754.6
1989	2747.6
1990	2762.5
1991	2699.5
1992	2748.4
1993	2882.8
1994	2990.3
1995	2820.2
1996	2898.1
1997	2813
1998	2842.2
1999	2963.2
2000	3100.4
2001	3157.6
2002	3160.6
2003	3286
2004	3383.5
2005	3493.7
2006	3610
2007	3723.5
2008	3824.8
2009	3839
2010	3855.2
2011	3643.4
2012	3610.5
2013	3646.1
2014	3690.2
2015	3710.9
2016	3659.7
2017	3671.5
2018	3761.3
2019	3714.3
2020	3727.6
2021	3743.6
2022	3456.7