Year	% of land area
1961	57.87835579473498
1962	57.95501586863529
1963	58.03167594253561
1964	58.11600202382595
1965	58.12366803121598
1966	58.19266209772627
1967	58.22945893319841
1968	58.23099213467642
1969	58.25552335832451
1970	58.27085537310458
1971	58.316851417444774
1972	58.33524983518083
1973	58.33708967695445
1974	58.338776198580256
1975	58.338776198580256
1976	58.338316238136855
1977	58.338316238136855
1978	58.338316238136855
1979	58.336783036658844
1980	58.336783036658844
1981	58.342915842570875
1982	58.34444904404887
1983	58.34444904404887
1984	58.34444904404887
1985	58.34444904404887
1986	58.34444904404887
1987	58.330650230746826
1988	58.32298422335679
1989	58.32298422335679
1990	58.32298422335679
1991	58.307652208576734
1992	58.307652208576734
1993	58.16046486668813
1994	57.974947487849384
1995	57.89828741394907
1996	57.88908820508103
1997	57.947349861245264
1998	58.05927356913973
1999	57.899820615427075
2000	57.94581665976726
2001	57.947349861245264
2002	57.93968385385524
2003	58.08380479278782
2004	58.1512656578201
2005	58.13440044156203
2006	58.12366803121598
2007	58.12980083712801
2008	58.13286724008402
2009	58.13286724008402
2010	58.13440044156203
2011	58.131334038606006
2012	58.12980083712801
2013	58.12366803121598
2014	58.12366803121598
2015	58.12366803121598
2016	58.12366803121598
2017	58.12366803121598
2018	58.27698817901661
2019	58.27698817901661
2020	58.741548226852494
2021	58.741548226852494