Year	% of land area
1961	0.803546047698136
1962	0.8248489048253803
1963	0.8225435856172216
1964	0.8363755008661738
1965	0.8428787778916587
1966	0.8479447880034149
1967	0.851929290338504
1968	0.8660458128971055
1969	0.8782127753846097
1970	0.8899243661766754
1971	0.9042685745829963
1972	0.9162932334156759
1973	0.9340422756688086
1974	0.9481035580811032
1975	0.961690865296509
1976	0.9792204499584211
1977	0.9983321190853653
1978	1.0135019175137514
1979	1.0342572186467731
1980	1.058242861471393
1981	1.073647464472076
1982	1.0813960153578697
1983	1.074811456369363
1984	1.0892854141094763
1985	1.1239212677684776
1986	1.1619810235037593
1987	1.207559022126751
1988	1.2392464769868403
1989	1.2544716324374674
1990	1.285174663235771
1991	1.300649170131436
1992	1.067774842593433
1993	1.0952000527320322
1994	1.1265211592955586
1995	1.139426972315285
1996	1.1533450226926216
1997	1.166566821436865
1998	1.1802538918306704
1999	1.2059451817603681
2000	1.2243660289581555
2001	1.248423531284376
2002	1.2661262290487667
2003	1.2903996056191704
2004	1.3204277379249372
2005	1.3527031014981243
2006	1.3865948482170785
2007	1.4212413187589665
2008	1.4385713485971663
2009	1.46379082494168
2010	1.4958235780507305
2011	1.5247659247779521
2012	1.5423238209018346
2013	1.568602417899492
2014	1.58560766716893
2015	1.616957383830945
2016	1.628807809114522
2017	1.6720183728282938
2018	1.7117273779690438
2019	1.7367053288575964
2020	1.752282269950508
2021	1.7674008701708284