Year	kg per hectare
1961	469.3
1962	486.1
1963	541.1
1964	477.8
1965	482.9
1966	453.4
1967	685.1
1968	552.1
1969	619.5
1970	648.2
1971	1619
1972	1753.5
1973	1160.6
1974	1554.3
1975	1418.7
1976	1469.2
1977	1322.5
1978	1803.3
1979	967.1
1980	1381.4
1981	1685.4
1982	901.5
1983	720.2
1984	1802.8
1985	2045.5
1986	1487
1987	1288.9
1988	1313.9
1989	1053.2
1990	1284
1991	1050.4
1992	1554.3
1993	1381.2
1994	1271.9
1995	2169.6
1996	1756.6
1997	1906
1998	1897.7
1999	1633.7
2000	1632.7
2001	1417.6
2002	996.5
2003	1023.9
2004	1246.5
2005	1317.1
2006	1423.1
2007	567.6
2008	1001.4
2009	1289.5
2010	1205.3
2011	1343.6
2012	1337.2
2013	1367.3
2014	1362.3
2015	1259.7
2016	1224.9
2017	1240.4
2018	1271.9
2019	1284.4
2020	1287
2021	1432.4
2022	1587.4