Year kg per hectare 1961 1813.6761246768758 1962 1974.7436350600926 1963 2014.3221050699017 1964 2056.8819138936624 1965 2157.2406119347274 1966 2186.4170391470134 1967 2412.417601779458 1968 2404.6747473592586 1969 2440.9333509349885 1970 2337.104753989371 1971 2751.6462456009262 1972 2794.7177020351965 1973 2817.8149312761284 1974 2920.0799150560797 1975 2831.7588355074427 1976 2840.282373068757 1977 2989.7436979623094 1978 3228.276119332342 1979 3109.566562448739 1980 3321.6929929273724 1981 3193.756989727136 1982 3482.867965988627 1983 3326.361510406022 1984 3925.6350942516356 1985 3693.4481042079033 1986 3695.5474635632827 1987 3692.349172625823 1988 3853.004011824574 1989 3827.612016767623 1990 3918.20424743689 1991 4092.9969080585306 1992 2574.5870978373014 1993 2620.675073921518 1994 2510.074520340918 1995 2535.6328375569883 1996 2706.139074866228 1997 2932.083087950867 1998 2922.937444986236 1999 2943.920887569621 2000 2890.647255908559 2001 3086.0954103724794 2002 3142.191932543955 2003 2898.7971476120256 2004 3392.401473740397 2005 3171.4438376556 2006 3124.131640018903 2007 3058.1024397439473 2008 3547.022587877041 2009 3431.939681055735 2010 3289.2785011961946 2011 3583.8675324284004 2012 3276.1227016798584 2013 3662.281651348368 2014 3899.6199291734642 2015 3803.3771237041224 2016 3818.7609872768116 2017 3966.4142722174092 2018 3839.0136337310905 2019 4028.2402037583115 2020 3932.6802168015183 2021 4031.1759069008917 2022 4043.058239863934