Year	% of land area
1961	0.1864032167869411
1962	0.19172902298085373
1963	0.19705482917476633
1964	0.20238063536867895
1965	0.20770644156259152
1966	0.21303224775650415
1967	0.2215535376667643
1968	0.23007482757702447
1969	0.23859611748728465
1970	0.2471174073975448
1971	0.255638697307805
1972	0.2641599872180651
1973	0.2726812771283253
1974	0.2812025670385855
1975	0.2897238569488456
1976	0.2982451468591058
1977	0.306766436769366
1978	0.3152877266796261
1979	0.3246611455809123
1980	0.333395467738929
1981	0.34191675764918916
1982	0.3515032087982318
1983	0.3728064335738822
1984	0.4047612707373579
1985	0.5219290070034351
1986	0.6390967432695125
1987	0.7456128671477644
1988	0.7775677043112401
1989	0.7988709290868905
1990	0.7988709290868905
1991	0.7988709290868905
1992	0.8308257662503661
1993	0.926690277740793
1994	0.9905999520677442
1995	1.109899193032986
1996	1.1397249534789837
1997	1.1716798587167123
1998	1.1716798587167123
1999	1.1716798587167123
2000	1.17168110674867
2001	1.171681830608424
2002	1.192985263692137
2003	1.2355919460580607
2004	1.278198592117509
2005	1.3154794824718379
2006	1.3421086789758483
2007	1.4113445343600508
2008	1.4486253333808823
2009	1.4912319290650795
2010	1.5444902122459752
2011	1.6190518086992294
2012	1.682961748516304
2013	1.7042650617886623
2014	1.7063953931158984
2015	1.7042650617886623
2016	1.7752762986767443
2017	1.846287343380687
2018	1.9172983987362873
2019	1.9918600031315874
2020	2.0131633186731017
2021	2.023814976443859