Year	% of land area
1961	6.795435361696063
1962	7.008466432076705
1963	7.1619364999324
1964	7.308098469318776
1965	7.476550139036574
1966	7.895669586252005
1967	8.163511395152538
1968	8.715272829586105
1969	8.761313849942814
1970	8.807354870299521
1971	8.85339589065623
1972	8.89943691101294
1973	8.945477931369647
1974	8.991518951726356
1975	9.037559972083063
1976	9.083600992439772
1977	9.12964201279648
1978	9.175683033153188
1979	9.221724053509897
1980	9.267765073866606
1981	9.313806094223313
1982	9.359847114580022
1983	9.40588813493673
1984	9.451929155293438
1985	9.497970175650147
1986	9.544011196006855
1987	9.590052216363564
1988	9.634631617026407
1989	9.6722683241434
1990	9.710635841107324
1991	9.749003358071247
1992	9.78737087503517
1993	9.825738391999094
1994	9.865202123733416
1995	9.904300450544271
1996	9.943398777355126
1997	9.982862509089447
1998	10.02123002605337
1999	10.060328352864227
2000	10.099792084598548
2001	10.138525006485938
2002	10.180911977607986
2003	10.899371138126716
2004	11.617830298645444
2005	12.347617011791618
2006	13.002020689226768
2007	13.514464553895401
2008	13.021679474109234
2009	12.603071593786655
2010	13.886519846968417
2011	14.114313276257084
2012	14.478402741998545
2013	14.393774961723835
2014	14.329609857163215
2015	14.74010574818485
2016	14.675575238700766
2017	14.757206698603056
2018	14.692478760838826
2019	14.911721714918388
2020	15.350207623077514
2021	15.423288607770703