Year	% of land area
1961	0.6724949562878278
1962	0.6724949562878278
1963	0.6724949562878278
1964	0.6724949562878278
1965	0.6724949562878278
1966	0.6724949562878278
1967	0.6724949562878278
1968	0.6724949562878278
1969	0.6724949562878278
1970	1.0087424344317417
1971	1.0087424344317417
1972	1.0087424344317417
1973	1.0087424344317417
1974	1.0087424344317417
1975	1.3449899125756557
1976	1.3449899125756557
1977	1.4794889038332213
1978	1.6812373907195695
1979	1.7484868863483525
1980	1.9502353732347006
1981	2.151983860121049
1982	2.2864828513786146
1983	2.42098184263618
1984	2.6227303295225286
1985	2.824478816408877
1986	3.026227303295225
1987	3.295225285810356
1988	3.5642232683254873
1989	3.698722259583053
1990	3.9004707464694013
1991	4.034969737726967
1992	4.034969737726967
1993	4.034969737726967
1994	4.034969737726967
1995	4.034969737726967
1996	4.169468728984533
1997	4.438466711499664
1998	4.438466711499664
1999	4.5057162071284464
2000	4.5057162071284464
2001	4.5057162071284464
2002	4.5057162071284464
2003	4.371217215870881
2004	4.371217215870881
2005	4.371217215870881
2006	4.371217215870881
2007	4.371217215870881
2008	4.707464694014795
2009	4.84196368527236
2010	4.84196368527236
2011	4.909213180901143
2012	4.969737726967048
2013	5.030262273032952
2014	5.090786819098857
2015	5.151311365164761
2016	5.211835911230666
2017	5.27236045729657
2018	5.332885003362475
2019	5.3732347007397445
2020	5.3732347007397445
2021	5.3732347007397445