Year	kg per hectare
1961	1192.7
1962	1323.1
1963	1490.7
1964	1622.7
1965	1746.5
1966	1879.1
1967	1935.7
1968	1939.4
1969	1900.4
1970	2127.7
1971	2174
1972	2106.5
1973	2275.7
1974	2389.2
1975	2480.4
1976	2522.3
1977	2486.9
1978	2791.8
1979	3032.5
1980	2937.3
1981	3081.6
1982	3456
1983	3716.1
1984	3954.9
1985	3820.5
1986	3889.9
1987	3973.1
1988	3930.6
1989	4014.7
1990	4306.5
1991	4231.4
1992	4361.6
1993	4562.1
1994	4504.9
1995	4659.3
1996	4891.6
1997	4813.2
1998	4952.8
1999	4944.9
2000	4752.6
2001	4800.3
2002	4869.1
2003	4871.1
2004	5186.8
2005	5224.6
2006	5313.4
2007	5320.6
2008	5549.7
2009	5449.6
2010	5527.5
2011	5710
2012	5828.7
2013	5897.7
2014	5896.3
2015	5985.2
2016	6018.6
2017	6110.8
2018	6122
2019	6264.2
2020	6295.8
2021	6316.7
2022	6379.6