Year	% of land area
1961	0.8742208915558706
1962	0.8955898534821392
1963	0.8872808442249568
1964	0.8969266990309432
1965	0.901371196309352
1966	0.905854770611495
1967	0.9143900152692442
1968	0.9316456062761156
1969	0.9405304874620135
1970	0.9553386227718436
1971	0.9725648457802194
1972	0.9858097802817559
1973	1.0042389610099005
1974	1.017196817621693
1975	1.0306478731786726
1976	1.04823522438417
1977	1.0673417615717231
1978	1.0849469239318366
1979	1.1069122433250624
1980	1.136489374401043
1981	1.1523052563106604
1982	1.157385259992943
1983	1.1413798467612493
1984	1.1518244498463959
1985	1.1879221143257859
1986	1.234045800468971
1987	1.2948796337053587
1988	1.3318343934760872
1989	1.3495610389201844
1990	1.3863171995184354
1991	1.4008323254522246
1992	1.0674907510876144
1993	1.0978797915883491
1994	1.1323954338017492
1995	1.1433529755117475
1996	1.1570276929690992
1997	1.17041019648226
1998	1.1813058315389824
1999	1.2088917815779878
2000	1.2245651307933372
2001	1.2503301098678874
2002	1.2685885256439935
2003	1.291811888880913
2004	1.323770963556358
2005	1.35615497559304
2006	1.394158605853357
2007	1.4282716814715528
2008	1.4432233703285693
2009	1.4682119386493713
2010	1.4974853382578115
2011	1.528213381297734
2012	1.5478161812402633
2013	1.5707123992932996
2014	1.5800837016860239
2015	1.6023658642133007
2016	1.6187495843093274
2017	1.6631318327050184
2018	1.6923796860885396
2019	1.7159145298109806
2020	1.727957483679657
2021	1.7428512127726596