Year	% of land area
1961	9.799937985146556
1962	9.837375063248588
1963	9.889317088138053
1964	9.922068875682232
1965	9.955182833435872
1966	9.997335499218396
1967	10.036074954947628
1968	10.083685687238518
1969	10.108813164005516
1970	10.101320007877662
1971	10.120829162303378
1972	10.204230961914934
1973	10.272913777606009
1974	10.323845220423154
1975	10.330982985418688
1976	10.403305363111855
1977	10.475633662173363
1978	10.552070830463665
1979	10.640168795814565
1980	10.63386572081189
1981	10.68880763781659
1982	10.811790153439091
1983	10.938825134815998
1984	11.143203030844548
1985	11.341301746596566
1986	11.358088177846522
1987	11.383002207794913
1988	11.376895355565006
1989	11.383277573582276
1990	11.387115099667453
1991	11.391762032922568
1992	11.069939306825303
1993	11.007992947443448
1994	10.951352767895232
1995	10.909281092609564
1996	10.870306354610316
1997	10.897276427752606
1998	10.892816122856306
1999	10.885469680847798
2000	10.841351402163406
2001	10.841536577295203
2002	10.844764247359432
2003	10.874458441788963
2004	10.893488896406437
2005	10.907832571437133
2006	10.945500600014139
2007	10.949332710940455
2008	10.920572630458292
2009	10.920642426586102
2010	10.93427478055795
2011	10.936928439196166
2012	10.933379755262086
2013	10.925113371865809
2014	10.91337576903677
2015	10.942600144196259
2016	10.938246800841004
2017	10.926630709971656
2018	10.910525277391573
2019	10.88354433345592
2020	10.924493058590475
2021	10.941412204995663