Year	kg per hectare
1961	505.2
1962	547.8
1963	560.1
1964	599.3
1965	467.5
1966	496.2
1967	571.3
1968	394
1969	493.7
1970	390.2
1971	424.8
1972	417.6
1973	323.9
1974	406
1975	346.4
1976	423.4
1977	431.3
1978	431.5
1979	447
1980	457.4
1981	415.6
1982	400.3
1983	401.9
1984	257.1
1985	425
1986	418.9
1987	326.5
1988	475.2
1989	352.7
1990	310.3
1991	333.2
1992	309.2
1993	326.2
1994	267.9
1995	312.3
1996	291
1997	287.7
1998	389.5
1999	380.1
2000	289.2
2001	394.4
2002	422.9
2003	429.5
2004	341.5
2005	436.6
2006	449.6
2007	424.8
2008	496.5
2009	386
2010	494.8
2011	362.8
2012	520.3
2013	407.7
2014	446.8
2015	551.3
2016	536.5
2017	541.9
2018	554.8
2019	501.5
2020	551.9
2021	360.6
2022	557.4