Year	% of land area
1961	0.43935736884924365
1962	0.46228960621399845
1963	0.46684567986262526
1964	0.4873986343219861
1965	0.49990252533543966
1966	0.5069897510110813
1967	0.5176205895245438
1968	0.5250115534434273
1969	0.5325543864839317
1970	0.5382747900649854
1971	0.5483993981730448
1972	0.5555372468892268
1973	0.5697218228486183
1974	0.5856850025851179
1975	0.6034113678139396
1976	0.6177736042748738
1977	0.6372641260847425
1978	0.6485028165829004
1979	0.6511353026455321
1980	0.6591340102973743
1981	0.6722458158785586
1982	0.6841426278923745
1983	0.694014450627243
1984	0.7039875228260588
1985	0.7242374156155327
1986	0.7361848523613223
1987	0.7444366836730328
1988	0.762560337719612
1989	0.7719765378667174
1990	0.7810889896219806
1991	0.7853920918397438
1992	0.7909101876248754
1993	0.7923783048521122
1994	0.8053888609693493
1995	0.8054901104332965
1996	0.8128306965694808
1997	0.8193106622621125
1998	0.837120883405623
1999	0.8452111560101859
2000	0.8594776459155384
2001	0.8711116497582593
2002	0.8751013190729539
2003	0.8918484208450169
2004	0.9067364392206825
2005	0.9246628305141108
2006	0.9398280831150277
2007	0.9657937575939985
2008	0.9761970883051372
2009	0.998163739284802
2010	1.0394912438965938
2011	1.0548365330771305
2012	1.095489942388763
2013	1.1285374969461774
2014	1.1681957631518336
2015	1.2295341982127066
2016	1.2227127326533402
2017	1.242544005213008
2018	1.3209562568886122
2019	1.346462690952048
2020	1.374200641081472
2021	1.3901327744468543