Year	% of land area
1961	0.8620937415023135
1962	0.8858596287215721
1963	0.8865228627835049
1964	0.9006718561047379
1965	0.9142681543743603
1966	0.9047617994866568
1967	0.8687260821216416
1968	0.8698314722248629
1969	0.8876282528867263
1970	0.8950343665783091
1971	0.9078568917756765
1972	0.9155946224982259
1973	0.9349389493045991
1974	0.9600737548888039
1975	0.9773618195445832
1976	0.99792389379357
1977	1.0341838956950091
1978	1.0528666405771532
1979	1.0772979223461105
1980	1.0915587157768596
1981	1.1072566434293118
1982	1.125718290738886
1983	1.1378786572302222
1984	1.1746914030630857
1985	1.2327295158626455
1986	1.2610300051515735
1987	1.271200493489782
1988	1.305691714810663
1989	1.3167465934391507
1990	1.3220529351808246
1991	1.3557703149977116
1992	1.382965316423791
1993	1.440671782864496
1994	1.4808009922859058
1995	1.5304373973278147
1996	1.5375125196500468
1997	1.5591800817618824
1998	1.5799421056006226
1999	1.607779251761595
2000	1.6548518867361355
2001	1.6819151913931136
2002	1.7001345931473018
2003	1.7202333242683328
2004	1.7695169349685709
2005	1.8142680454311293
2006	1.8366883010641426
2007	1.8666258741645276
2008	1.9135326859596409
2009	1.9382191806566156
2010	1.9651719365273088
2011	1.9894715215271652
2012	1.9988470203785633
2013	2.023036056592135
2014	2.0541896663416535
2015	2.1593004141157532
2016	2.125009142384626
2017	2.1575998863558477
2018	2.3041664289867763
2019	2.3203959525878366
2020	2.334195209187761
2021	2.3645961489416107