Year	kg per hectare
1961	465
1962	477.4
1963	513.3
1964	502.1
1965	452.5
1966	467.7
1967	463.2
1968	571.7
1969	726.7
1970	812.5
1971	902.7
1972	974.3
1973	859
1974	919.6
1975	970.5
1976	830.9
1977	844
1978	757.2
1979	822.6
1980	635.7
1981	728
1982	868.6
1983	748.5
1984	892.4
1985	840.4
1986	787.9
1987	721.3
1988	843.8
1989	917.9
1990	746.8
1991	762.7
1992	863.3
1993	877.6
1994	721.7
1995	849.3
1996	811.4
1997	981.1
1998	835.4
1999	1060.8
2000	1058.3
2001	1150.3
2002	1131.1
2003	1154.7
2004	1094.8
2005	1132.6
2006	1130.7
2007	1121.6
2008	1144.4
2009	1242.9
2010	1187.4
2011	1226.3
2012	1112.4
2013	1090.1
2014	1153.1
2015	1236.2
2016	1130.8
2017	1137.2
2018	1145.2
2019	1143
2020	1150.3
2021	1149.5
2022	1167.8