Year	% of land area
1961	66.16344897662941
1962	66.9719843228335
1963	67.01843518652925
1964	67.63826389896937
1965	68.33793003338656
1966	69.00420960952243
1967	69.42371897227464
1968	69.71839163884454
1969	69.908549862099
1970	69.59355494266222
1971	70.02467702133836
1972	70.0740310640151
1973	70.28596312962694
1974	70.3846712149804
1975	70.19160981274496
1976	70.43112207867614
1977	70.84917985193788
1978	70.91450137901002
1979	71.07272463347365
1980	71.58513572361737
1981	71.25997967774713
1982	71.05820873856872
1983	70.7867615038467
1984	71.03208012773987
1985	70.88982435767164
1986	70.32805922485122
1987	69.92306575700393
1988	69.68355349107273
1989	67.88648570184353
1990	65.86442154158803
1991	64.52024967339236
1992	64.10509507911163
1993	63.97590361445783
1994	63.77703585426041
1995	63.7059079692263
1996	63.02511249818551
1997	63.226012483669614
1998	63.42691246915372
1999	63.627812454637834
2000	63.814196545217015
2001	64.01509653070111
2002	63.478008419219044
2003	63.434460734504285
2004	62.49092756568443
2005	62.44737988096966
2006	61.83771229496299
2007	62.06996661344172
2008	67.19407751487878
2009	66.68485992161418
2010	66.30860792567861
2011	66.11990129191466
2012	65.80055160400639
2013	64.98766148933082
2014	64.82798664537668
2015	64.30541442879954
2016	64.75540717085208
2017	65.16185222818987
2018	65.55378139062273
2019	65.6699085498621
2020	65.49571781100305
2021	62.95543620264189