Year	% of land area
1961	0.2716140827514348
1962	0.27817814733077495
1963	0.2873678377418512
1964	0.300426871483907
1965	0.3099620389781064
1966	0.31887534772268417
1967	0.327581370217388
1968	0.3392584956269511
1969	0.343611506874303
1970	0.3496228081206461
1971	0.35549591853373996
1972	0.36240546019620334
1973	0.373405450522845
1974	0.38088519202837967
1975	0.3965121469547276
1976	0.4093438751128045
1977	0.4176357834540497
1978	0.42185083686084934
1979	0.4254439971420556
1980	0.4342196001365401
1981	0.4443080886183884
1982	0.4517708061255091
1983	0.4577824396729119
1984	0.4648996609991473
1985	0.4749190502448186
1986	0.4818980730987
1987	0.48873889748022725
1988	0.4926084547061417
1989	0.49972567603237716
1990	0.5098832637504025
1991	0.5164476911872217
1992	0.5174841797298773
1993	0.5044935233285931
1994	0.505944607288311
1995	0.49792909589177403
1996	0.5065665004139044
1997	0.5071883935394979
1998	0.5132000270869006
1999	0.5201099507046049
2000	0.5295765460608598
2001	0.5306130346035155
2002	0.537661156693574
2003	0.5469967350182252
2004	0.5530662512039188
2005	0.559220343729802
2006	0.570982726822335
2007	0.5910893250730568
2008	0.5864740237057485
2009	0.6017595227933554
2010	0.639519389247623
2011	0.6506550402164967
2012	0.6591502111208537
2013	0.6877169139263517
2014	0.7230117861812102
2015	0.7398280528980121
2016	0.7505429194320542
2017	0.7641003751770007
2018	0.7822816220739277
2019	0.8063563721064183
2020	0.8324685328078026
2021	0.8352490794346963