Year	kg per hectare
1961	985
1962	1595.4
1963	1838.9
1964	1527.2
1965	1730.4
1966	1972.7
1967	1519
1968	1734.5
1969	1959.2
1970	2110.8
1971	2145.2
1972	1987.7
1973	1951.3
1974	1726.7
1975	2052.2
1976	2275.8
1977	2265.9
1978	2267.4
1979	2032.7
1980	2141.2
1981	2346.4
1982	2482.8
1983	2204.6
1984	2028
1985	2222.1
1986	2570.4
1987	2396.6
1988	1754.4
1989	2193.6
1990	2636.3
1991	2580.5
1992	2460.3
1993	2647
1994	2594.5
1995	2699.8
1996	2844.2
1997	2584.6
1998	2782.6
1999	3087.8
2000	2805.7
2001	2446.8
2002	2375.4
2003	2758.8
2004	3141.9
2005	3215.9
2006	3046.3
2007	2973.4
2008	3391.7
2009	3299.5
2010	3501.1
2011	3552.4
2012	3456.3
2013	4160.4
2014	3647
2015	3673
2016	4239.1
2017	4104.8
2018	3914.7
2019	4010.8
2020	4091.9
2021	3120
2022	4078.7