Year	% of land area
1961	1.3065515204223155
1962	1.3128903110317776
1963	1.3172006886462118
1964	1.3303853731138928
1965	1.3341886474795701
1966	1.3108618980367497
1967	1.2213581746311457
1968	1.2276969652406078
1969	1.2566018504197547
1970	1.2763788771212763
1971	1.279421496613818
1972	1.2997056265640965
1973	1.3273427536213511
1974	1.356399769775125
1975	1.3859131788527803
1976	1.4122825477881424
1977	1.4503152914449147
1978	1.4655283889076236
1979	1.5181403509661584
1980	1.5502146314500365
1981	1.5683435725930979
1982	1.5885009267311871
1983	1.602065938635436
1984	1.6752155822686279
1985	1.7455761580336564
1986	1.7946130421884547
1987	1.7883629946475252
1988	1.7928635359802432
1989	1.7971105256885829
1990	1.7980613442800022
1991	1.8677246530779898
1992	1.797513142626969
1993	1.90708271444167
1994	1.9340316796242936
1995	2.010873421111053
1996	2.0256467179478963
1997	2.0502383638831225
1998	2.0720378452728885
1999	2.1092857780412277
2000	2.1758085451039797
2001	2.208187848026008
2002	2.2324579138109004
2003	2.2524074471094537
2004	2.3083124592021185
2005	2.3459188610305586
2006	2.3528364179349834
2007	2.37602951994473
2008	2.420103302855726
2009	2.438380653505833
2010	2.478342924959736
2011	2.4934363126541315
2012	2.4940807393995574
2013	2.4956396002611103
2014	2.500160396953348
2015	2.502389059816584
2016	2.5062258228360834
2017	2.5469157894592795
2018	2.5512953760208843
2019	2.555259691756804
2020	2.561407830097021
2021	2.576960436507312