Year	% of land area
1961	0.8721218508712858
1962	0.8822403439019215
1963	0.8969712554080607
1964	0.9036880898130125
1965	0.913604789535345
1966	0.9208981762497348
1967	0.9295752885067756
1968	0.9388866083041982
1969	0.9500428954918222
1970	0.9599884228296265
1971	0.9741427820263276
1972	0.9871440366041531
1973	1.001903775725764
1974	1.013106187098143
1975	1.0195751040100367
1976	1.0426411037789398
1977	1.0569973100851195
1978	1.0812414255539895
1979	1.1076908618710979
1980	1.1333331219300276
1981	1.1458011123465393
1982	1.1488136094529564
1983	1.1596095919060978
1984	1.1695983981010603
1985	1.2182451815180853
1986	1.2778147893716796
1987	1.3468961045962058
1988	1.3915718691002261
1989	1.4103026824485
1990	1.4555550014226482
1991	1.463909653275187
1992	0.9953901578211726
1993	1.025764497511451
1994	1.0665407487166811
1995	1.0759837989661267
1996	1.0797920455183496
1997	1.0920083552902953
1998	1.101730122376944
1999	1.125968569315695
2000	1.1414603715315323
2001	1.1627592935587208
2002	1.180525711747569
2003	1.2004818974167855
2004	1.2267888838487266
2005	1.2486117837420072
2006	1.2841083178225692
2007	1.3163435177222915
2008	1.3283686137072839
2009	1.3514960166617391
2010	1.362668844387831
2011	1.39722782958326
2012	1.412461188647285
2013	1.4304861923958265
2014	1.439398659251976
2015	1.4571695330133128
2016	1.4738766512885637
2017	1.5337721154383903
2018	1.5673334667887673
2019	1.5916622505406506
2020	1.607176573853389
2021	1.6184707418459592