Year	kg per hectare
1961	946.2
1962	1010.6
1963	919.6
1964	991.9
1965	983.6
1966	975.8
1967	997.3
1968	1045.7
1969	1066.6
1970	1092.3
1971	1110.7
1972	1024.8
1973	1110
1974	973.3
1975	1104.7
1976	1104.8
1977	1110.1
1978	1234.2
1979	1100
1980	1063.5
1981	1080.4
1982	1075.4
1983	1094
1984	1108.9
1985	1152.5
1986	1213.5
1987	1228.2
1988	1194.3
1989	1369
1990	1348.5
1991	1368.9
1992	1391.4
1993	1394.1
1994	1274.8
1995	1331.9
1996	1386.3
1997	1434
1998	1275.9
1999	1309.5
2000	1228.2
2001	1283.5
2002	1308.8
2003	1284.1
2004	1328.1
2005	1344.3
2006	1277
2007	1303.1
2008	1281.8
2009	1296.9
2010	1231.7
2011	1153.8
2012	1107.5
2013	1178.4
2014	1332.4
2015	1203.9
2016	1482.5
2017	1125.4
2018	1322.8
2019	1445.7
2020	1278.7
2021	1478.5
2022	1483.5