Year	% of land area
1961	0.7951434576201983
1962	0.8162438503985731
1963	0.8145370997759257
1964	0.8284939153514456
1965	0.8348818424802412
1966	0.8404287820038453
1967	0.8437734626595171
1968	0.8581156735369252
1969	0.8678056125558266
1970	0.8802621392775677
1971	0.8936079217854882
1972	0.9052247669597544
1973	0.922722496727804
1974	0.9365981999324291
1975	0.9512799356210564
1976	0.9685102980232009
1977	0.9872571504927394
1978	1.0022326097341916
1979	1.0209450516815761
1980	1.0444074394760146
1981	1.0597614334813639
1982	1.067269818716611
1983	1.0612046242842972
1984	1.074621148650605
1985	1.1081860446167426
1986	1.144984114059
1987	1.1888974562678996
1988	1.2193794492216887
1989	1.2346446681952004
1990	1.2638911947285756
1991	1.2790363325151215
1992	1.057075147210761
1993	1.0837075306780386
1994	1.1141349158591833
1995	1.1267014440808278
1996	1.1398351392538026
1997	1.152490172962547
1998	1.1655738750234137
1999	1.1907266667679666
2000	1.208534360329591
2001	1.2326250619160968
2002	1.2505489500679996
2003	1.2730650821326175
2004	1.3024683373680719
2005	1.3351051906197153
2006	1.3678113691508738
2007	1.401811132787394
2008	1.4187770092855947
2009	1.443512140946507
2010	1.4753125553122692
2011	1.503238948649104
2012	1.520266031556056
2013	1.5458010815923422
2014	1.5614925858288675
2015	1.5910273924512066
2016	1.6026008419231257
2017	1.6428384200460122
2018	1.6813705966359236
2019	1.7052748302456073
2020	1.7209148123814775
2021	1.7358788141163666