Year	% of land area
1961	3.463393248575186
1962	3.463393248575186
1963	3.5072336694432265
1964	3.5072336694432265
1965	3.5072336694432265
1966	3.5510740903112668
1967	3.5510740903112668
1968	3.5510740903112668
1969	3.5949145111793075
1970	3.5949145111793075
1971	3.638754932047348
1972	3.638754932047348
1973	3.682595352915388
1974	3.682595352915388
1975	3.7264357737834284
1976	3.7264357737834284
1977	3.7702761946514687
1978	4.077159140727751
1979	4.1209995615957915
1980	4.208680403331872
1981	4.252520824199912
1982	4.252520824199912
1983	4.252520824199912
1984	4.252520824199912
1985	4.427882507672074
1986	4.515563349408154
1987	4.910127137220517
1988	5.041648399824639
1989	5.26085050416484
1990	5.523893029373082
1991	5.699254712845243
1992	5.962297238053485
1993	6.269180184129768
1994	6.269180184129768
1995	6.400701446733889
1996	6.444541867601929
1997	6.488382288469969
1998	6.488382288469969
1999	6.57606313020605
2000	6.53222270933801
2001	6.53222270933801
2002	6.6637439719421305
2003	6.6637439719421305
2004	6.6637439719421305
2005	6.6637439719421305
2006	6.6637439719421305
2007	6.6637439719421305
2008	6.6637439719421305
2009	6.795265234546252
2010	6.882946076282333
2011	6.882946076282333
2012	7.014467338886453
2013	7.014467338886453
2014	7.014467338886453
2015	7.452871547566857
2016	7.452871547566857
2017	7.540552389302937
2018	7.540552389302937
2019	7.628233231039018
2020	7.89127575624726
2021	7.97895659798334