Year	% of land area
1961	36.237266383251786
1962	36.2436833239753
1963	36.24127697120398
1964	36.247693911927485
1965	36.24528755915617
1966	36.251704499879686
1967	36.25731932301275
1968	36.26373626373626
1969	36.277372262773724
1970	36.25972567578407
1971	36.24127697120398
1972	36.22363038421433
1973	36.20518167963424
1974	36.18753509264458
1975	36.16988850565493
1976	35.99101628298709
1977	35.973369695997434
1978	35.954920991417346
1979	35.9292532285233
1980	35.90679393599102
1981	35.87711558514478
1982	35.85866688056469
1983	35.83700970562285
1984	35.81455041309056
1985	35.79690382610091
1986	35.73032806609449
1987	35.71268147910484
1988	35.69503489211519
1989	35.676586187535094
1990	35.658939600545445
1991	35.68059677548729
1992	35.70305606801957
1993	35.70225395042913
1994	35.70225395042913
1995	35.68621159862036
1996	35.65172054223149
1997	35.65412689500281
1998	35.70466030320045
1999	35.74797465308414
2000	35.71268147910484
2001	35.62605277933745
2002	35.64450148391754
2003	35.693430656934304
2004	35.541830432341385
2005	35.43996149835566
2006	35.403064089195475
2007	35.48969278896286
2008	35.449586909440924
2009	35.79850806128179
2010	35.97497393117831
2011	36.34876072832277
2012	36.33833319964707
2013	36.486724953878245
2014	36.63591882569985
2015	36.72816234860031
2016	36.75623646426566
2017	36.714526349562846
2018	36.73056870137162
2019	36.79874869655892
2020	36.8107804604155
2021	36.81479104836769