Year	kg per hectare
1961	2763.4
1962	2897
1963	2705.3
1964	2890.2
1965	2994.4
1966	3330.9
1967	3527.9
1968	3267.7
1969	3479.6
1970	3708.3
1971	3391.6
1972	3284.2
1973	3640.6
1974	3656.4
1975	3675.3
1976	3559.9
1977	4077.4
1978	4051.7
1979	3999.7
1980	3959.5
1981	3958.1
1982	4144.6
1983	3649.7
1984	4031.7
1985	3990.2
1986	3985.5
1987	3812.7
1988	3811.1
1989	3731.5
1990	3765.1
1991	3813.4
1992	3795.1
1993	3694
1994	3626.9
1995	3515.7
1996	3700.7
1997	3980.8
1998	3756.5
1999	3718.6
2000	3896
2001	3765.8
2002	3921.2
2003	3693.8
2004	3559.2
2005	3597.7
2006	4128.7
2007	4252.7
2008	4188.7
2009	4208.9
2010	4232.4
2011	4132.7
2012	4361.9
2013	4495.8
2014	4433
2015	4529.6
2016	4433
2017	4879
2018	4868.4
2019	4555.3
2020	4319.1
2021	4638.3
2022	4758.6