Year	kg per hectare
1961	1075.3
1962	1080.5
1963	1039
1964	1087.7
1965	1064
1966	1011.1
1967	960.3
1968	1040.4
1969	1016.4
1970	1109.1
1971	1112.4
1972	1042.3
1973	1056.1
1974	1043
1975	990.7
1976	813.3
1977	805.8
1978	1093.6
1979	1197
1980	1325.1
1981	1329.4
1982	1230.9
1983	1251.4
1984	1434.5
1985	1262.4
1986	1276.2
1987	1117.7
1988	1196.6
1989	1112.9
1990	1003.9
1991	1112.7
1992	1238.1
1993	1189.2
1994	1163.5
1995	1035.2
1996	1104.3
1997	940.6
1998	1036.4
1999	1303.7
2000	1305.3
2001	1292.5
2002	966.5
2003	1207.7
2004	1179
2005	1047.4
2006	1033
2007	805.3
2008	983.5
2009	1058.1
2010	1136.4
2011	879.6
2012	920.5
2013	969.6
2014	753.4
2015	800.2
2016	743.9
2017	634.2
2018	536.8
2019	461.4
2020	656.3
2021	1056.8
2022	929.6