Year	% of land area
1961	0.4280714277954485
1962	0.4319986886009113
1963	0.4361809663417938
1964	0.44719769795192327
1965	0.4513799756928058
1966	0.45979553456165473
1967	0.44709569117775544
1968	0.4551032229499329
1969	0.46234570391585134
1970	0.4684661103659233
1971	0.47147531020387534
1972	0.47989086907272427
1973	0.4924479029727885
1974	0.500419740937291
1975	0.5079277544266243
1976	0.5169404206655591
1977	0.5248462682435722
1978	0.531681000988435
1979	0.5443303571132557
1980	0.5527972648419665
1981	0.5588159100949054
1982	0.5664157248634469
1983	0.5722813537116501
1984	0.5917654425813337
1985	0.6096683619354147
1986	0.6235418492981214
1987	0.6279793250354577
1988	0.6300195437652675
1989	0.6339469648201514
1990	0.6391495225811664
1991	0.6563089070778693
1992	0.6986039958147171
1993	0.7082641702001851
1994	0.7178252658740073
1995	0.7268909679896003
1996	0.7319439822835374
1997	0.7336283203815165
1998	0.7361052881726621
1999	0.7448242147974947
2000	0.7624602254704518
2001	0.7734926400122144
2002	0.7887016129675471
2003	0.7955455355160821
2004	0.8045898639862648
2005	0.814675305482334
2006	0.8245346768028637
2007	0.8488154850647921
2008	0.8616273411130524
2009	0.8793763777310153
2010	0.9158630225229625
2011	0.9317375207366785
2012	0.9388888538530796
2013	0.9660653859008365
2014	0.9889480180124736
2015	1.0021698216946455
2016	1.0125878039193572
2017	1.0292289225274551
2018	1.0413169580336705
2019	1.0584192802026469
2020	1.0793280053199161
2021	1.0827675031102024