Year	kg per hectare
1991	1200.4
1992	1208.9
1993	1206.1
1994	1213.2
1995	1193.5
1996	1217.9
1997	1220.9
1998	1224
1999	1227.3
2000	1230.8
2001	1234.7
2002	1238.9
2003	1243.5
2004	1254.6
2005	1272.2
2006	1287.4
2007	1192.9
2008	1366.1
2009	1421.4
2010	1475.2
2011	1528.1
2012	1674.3
2013	1673.8
2014	1670.5
2015	1678.1
2016	1697.3
2017	1722.4
2018	1741.9
2019	1704.5
2020	1718
2021	1719
2022	1712.9