Year	% of land area
1961	0.16561409707194275
1962	0.16561409707194275
1963	0.16561409707194275
1964	0.16561409707194275
1965	0.16561409707194275
1966	0.17665503687673895
1967	0.18769597668153512
1968	0.18769597668153512
1969	0.20094510444729055
1970	0.22523517201784218
1971	0.23848429978359756
1972	0.25173342754935296
1973	0.2649825553151084
1974	0.2782316830808638
1975	0.29148081084661925
1976	0.3047299386123747
1977	0.3179790663781301
1978	0.3533100737534779
1979	0.3643510135582741
1980	0.36876738948019255
1981	0.37980832928498875
1982	0.38643289316786644
1983	0.39526564501170336
1984	0.39747383297266264
1985	0.40409839685554033
1986	0.4085147727774588
1987	0.4107229607384181
1988	0.41513933666033653
1989	0.41955571258225505
1990	0.4239720885041735
1991	0.4239720885041735
1992	0.4239720885041735
1993	0.4261802764651327
1994	0.4261802764651327
1995	0.42838846442609196
1996	0.4305966523870512
1997	0.43501302830896965
1998	0.4394294042308881
1999	0.4482621560747251
2000	0.45267853199664354
2001	0.4637194718014398
2002	0.4858013514110321
2003	0.4968422912158283
2004	0.5078832310206245
2005	0.5299651106302168
2006	0.5697124939274831
2007	0.5807534337322793
2008	0.6514154484829748
2009	0.662456388287771
2010	0.662456388287771
2011	0.662456388287771
2012	0.662456388287771
2013	0.662456388287771
2014	0.6955792077021596
2015	0.7066201475069558
2016	0.7198692752727112
2017	0.7287020271165482
2018	0.7287020271165482
2019	0.726493839155589
2020	0.7309102150775074
2021	0.7309102150775074