Year	% of land area
1961	1.6534095987130217
1962	1.6534095987130217
1963	1.6534095987130217
1964	1.6712842970774868
1965	1.6712842970774868
1966	1.707033693806417
1967	1.7427830905353472
1968	1.769595138082045
1969	1.8053445348109751
1970	1.8768433282688353
1971	1.8947180266333006
1972	1.8947180266333006
1973	1.8947180266333006
1974	1.8947180266333006
1975	1.984091518455626
1976	2.0734650102779515
1977	2.1628385021002767
1978	2.261149343104835
1979	2.350522834927161
1980	2.439896326749486
1981	2.529269818571812
1982	2.618643310394137
1983	2.708016802216463
1984	2.797390294038788
1985	2.8867637858611137
1986	2.9850746268656714
1987	3.074448118687997
1988	3.1638216105103227
1989	3.2531951023326484
1990	3.1995710072392525
1991	3.1280722137813926
1992	3.038698721959067
1993	2.9671999285012065
1994	3.038698721959067
1995	3.1280722137813926
1996	3.1280722137813926
1997	3.172758959692555
1998	3.172758959692555
1999	3.2085083564214854
2000	3.2085083564214854
2001	3.217445705603718
2002	3.217445705603718
2003	3.3068191974260435
2004	3.4855661810706944
2005	3.5749396728930196
2006	3.6643131647153453
2007	3.6643131647153453
2008	3.6643131647153453
2009	3.735811958173206
2010	4.289927607471624
2011	4.5580480829386
2012	4.826168558405577
2013	4.826168558405577
2014	4.826168558405577
2015	4.826168558405577
2016	4.826168558405577
2017	5.0942890338725535
2018	5.147913128965949
2019	5.147913128965949
2020	5.147913128965949
2021	5.36240950933953