Year	% of land area
1961	0.5033160111643556
1962	0.5266646965487357
1963	0.5397578825958401
1964	0.5643013834369902
1965	0.5759010501631321
1966	0.5896912118933524
1967	0.5987021117964927
1968	0.6075636597675367
1969	0.6154295281912724
1970	0.620756413769372
1971	0.6267304910532219
1972	0.6327045683370718
1973	0.6459570631117455
1974	0.6590683519741533
1975	0.6738134246308546
1976	0.6883856736122907
1977	0.70247500214576
1978	0.7110381276148648
1979	0.7152201191230324
1980	0.7221901049699783
1981	0.7358811485979077
1982	0.7467841978870587
1983	0.754749895997854
1984	0.7638606632120761
1985	0.7838744797154493
1986	0.7949766714573703
1987	0.806477148104831
1988	0.8258935372498944
1989	0.8371799357606275
1990	0.8532258388925609
1991	0.8597385284987944
1992	0.8627065997245663
1993	0.8585925095969346
1994	0.8755165947712997
1995	0.8799207987111929
1996	0.8908285438023283
1997	0.8984086681388779
1998	0.9172346189416688
1999	0.9313627522085737
2000	0.9456214961793451
2001	0.9621325103419948
2002	0.9775375989014342
2003	0.9981439459723894
2004	1.015067724874853
2005	1.0475148266577732
2006	1.067339777822819
2007	1.1032443662748295
2008	1.1213856098020876
2009	1.146625350287645
2010	1.1854142913502206
2011	1.2064189754872476
2012	1.2198574223694885
2013	1.2595085600199343
2014	1.2992106298792823
2015	1.3591622394030642
2016	1.355881726297194
2017	1.3818205076212575
2018	1.4594087744398332
2019	1.4888037724694927
2020	1.5187798730182906
2021	1.5338480624326756