Year kg per hectare 1961 1272.484361458881 1962 1335.198599940184 1963 1308.2440512982685 1964 1388.3156169156175 1965 1362.903082204468 1966 1366.6011239963048 1967 1429.9713327613126 1968 1347.6246356775507 1969 1412.7567560722541 1970 1533.1161227359291 1971 1494.0110584815197 1972 1445.664121961755 1973 1613.6702305205008 1974 1661.0803256628433 1975 1624.802097658824 1976 1629.0781105240549 1977 1691.7725673866828 1978 1710.2083625732785 1979 1726.193597769889 1980 1796.689896243902 1981 1994.8993986526057 1982 1985.6734922269127 1983 1981.486549660637 1984 2094.1273553580095 1985 2138.555439320874 1986 2033.7898946927505 1987 2097.1703677742744 1988 2092.034620994587 1989 2109.240054717389 1990 2090.1830899439747 1991 2143.3167524126256 1992 2423.569417114625 1993 2530.142462853889 1994 2435.0664687416634 1995 2569.5850527085327 1996 2517.747348153807 1997 2663.4497113558564 1998 2853.9532874871365 1999 2810.3917908926105 2000 2851.8299304818797 2001 3043.5026632780427 2002 2938.8157031661312 2003 3189.7403285957266 2004 3190.0299007654166 2005 3210.029038605297 2006 3268.2007786316876 2007 3544.0909598294193 2008 3662.1102082863003 2009 3344.9047712964443 2010 3869.3219937233084 2011 3817.7502175135373 2012 3971.247129129658 2013 4168.645441498453 2014 4178.510628805552 2015 4360.498272748027 2016 4191.40157296325 2017 4689.555626207162 2018 4346.474306105397 2019 4860.599405630767 2020 4721.754563425142 2021 4439.830195112448 2022 4591.732428480137