Year	kg per hectare
1961	546.1
1962	489.9
1963	503.5
1964	529.3
1965	551.5
1966	531.8
1967	577.5
1968	573.8
1969	556.8
1970	577.1
1971	532.7
1972	555.8
1973	687.7
1974	707.9
1975	739.3
1976	724.6
1977	754
1978	741.1
1979	720.9
1980	718.3
1981	653.8
1982	649.5
1983	599.9
1984	799.1
1985	855.8
1986	836.2
1987	725.1
1988	834.7
1989	853.7
1990	847.9
1991	878.6
1992	913.4
1993	919.2
1994	956.9
1995	1086.5
1996	1009.6
1997	1117
1998	1055.9
1999	1162.6
2000	1102.1
2001	1069.3
2002	1131.1
2003	1148.7
2004	1146
2005	1136.4
2006	1190.5
2007	1286
2008	1158.7
2009	1423.5
2010	1200.6
2011	1517.8
2012	1373.2
2013	1479.6
2014	1460.3
2015	1336.7
2016	1455.9
2017	1405.4
2018	1428.5
2019	1238.3
2020	1432.8
2021	1408.6
2022	1361.5