Year	% of land area
1961	4.9937604571382055
1962	5.033145182678557
1963	5.122191110988941
1964	5.1613733443671315
1965	5.206478473488536
1966	5.231334386393823
1967	5.257405252272076
1968	5.332023614028475
1969	5.371712077812068
1970	5.384519707068764
1971	5.430991658284757
1972	5.459188691865703
1973	5.468857692608899
1974	5.447048214511986
1975	5.487923444875311
1976	5.523607132639987
1977	5.541065911831663
1978	5.612693159297654
1979	5.6238744767870665
1980	5.636372032245322
1981	5.633327800050129
1982	5.665720880236515
1983	5.693962727338586
1984	5.720736462275893
1985	5.792464959205832
1986	5.805924384571586
1987	5.797817679179024
1988	5.8298563862415955
1989	5.841847694380113
1990	5.921220525838079
1991	5.9815584580739385
1992	6.042250758371141
1993	6.204901273925818
1994	6.224790045314704
1995	6.391541159096776
1996	6.528018688221057
1997	6.587597249477312
1998	6.609220241934581
1999	6.652510624739061
2000	6.657224966842066
2001	6.693757955360225
2002	6.78036083385211
2003	7.052504873769509
2004	7.087698856189256
2005	7.274776911349222
2006	7.355009496953121
2007	7.500440924358443
2008	7.619668723622751
2009	7.811669965011077
2010	7.976893315725069
2011	8.127191066072067
2012	8.503974596950918
2013	8.668950827801108
2014	8.743839996608704
2015	8.819277779775405
2016	8.926672719784255
2017	9.018717991563605
2018	9.10391058418446
2019	9.14043413812233
2020	9.177198283152443
2021	9.21568253691361