Year	kg per hectare
1971	3220
1972	4360
1973	3450
1974	3630.8
1975	3728.6
1976	3430.8
1977	2163.7
1978	2569.1
1979	2409.1
1980	2623
1981	2837.8
1982	3758.2
1983	3190.5
1984	3238.5
1985	3219.7
1986	3262.4
1987	3254.3
1988	3227.2
1989	3050
1990	2897.4
1991	2781.2
1992	3145.4
1993	3048.3
1994	3169.8
1995	3188
1996	3377.8
1997	3377
1998	3362.6
1999	3797.9
2000	4099.4
2001	4046.7
2002	4069.6
2003	3706.4
2004	4121.6
2005	3649.2
2006	3547.4
2007	4155.2
2008	4921.9
2009	6323.6
2010	7592.6
2011	6049.8
2012	6076.4
2013	5719
2014	6494.7
2015	5845.8
2016	4692.7
2017	4996.4
2018	8709.4
2019	6594.9
2020	7124.6
2021	8431.1
2022	9148.5