Year	% of land area
1961	55.66426364572605
1962	55.651390319258496
1963	55.63851699279093
1964	56.16632337796087
1965	56.1534500514933
1966	56.140576725025745
1967	56.12770339855818
1968	56.114830072090626
1969	57.08032955715757
1970	58.2711122554068
1971	58.303295571575696
1972	58.9340885684861
1973	59.5005149330587
1974	59.809474768280126
1975	60.24716786817713
1976	60.68486096807415
1977	60.97451081359423
1978	60.2278578784758
1979	59.8159114315139
1980	58.32260556127703
1981	58.75386199794027
1982	59.320288362512876
1983	59.99613800205973
1984	60.131307929969104
1985	59.783728115345
1986	59.178681771369725
1987	59.255921730175075
1988	59.02420185375901
1989	59.33959835221421
1990	59.159371781668376
1991	59.2816683831102
1992	60.21498455200825
1993	60.64624098867147
1994	59.7515447991761
1995	60.16992790937178
1996	60.01544799176107
1997	60.163491246138
1998	60.633367662203916
1999	61.31565396498455
2000	61.47657054582905
2001	61.1418640576725
2002	62.84114315139032
2003	62.97631307929969
2004	63.27239958805355
2005	63.23377960865088
2006	63.117919670442845
2007	63.11148300720907
2008	63.600669412976316
2009	63.0084963954686
2010	64.61122554067971
2011	64.83007209062822
2012	63.86457260556128
2013	63.99974253347065
2014	62.82826982492276
2015	63.29814624098867
2016	62.452368692070024
2017	62.711766220391354
2018	62.4388516992791
2019	62.4388516992791
2020	62.4388516992791
2021	62.4388516992791