Year	% of land area
1961	0.19458281444582815
1962	0.19458281444582815
1963	0.19458281444582815
1964	0.2010689082606891
1965	0.2010689082606891
1966	0.2010689082606891
1967	0.20755500207555005
1968	0.20755500207555005
1969	0.20755500207555005
1970	0.21404109589041095
1971	0.21404109589041095
1972	0.21404109589041095
1973	0.24647156496471564
1974	0.2724159402241594
1975	0.3048464092984641
1976	0.3268991282689913
1977	0.3541407222914072
1978	0.3463574097135741
1979	0.37230178497301786
1980	0.39694894146948945
1981	0.4462432544624325
1982	0.47867372353673726
1983	0.47867372353673726
1984	0.5059153175591532
1985	0.5292652552926526
1986	0.5591012868410129
1987	0.5461290992112909
1988	0.5539124117891241
1989	0.5837484433374844
1990	0.5915317559153176
1991	0.5967206309672063
1992	0.5967206309672063
1993	0.6745537567455375
1994	0.7004981320049813
1995	0.7342258198422582
1996	0.8068700705687006
1997	0.8159506019095061
1998	0.8302200083022002
1999	0.8380033208800332
2000	0.8535699460356995
2001	0.8717310087173101
2002	0.8613532586135326
2003	0.8457866334578663
2004	0.9534557907845579
2005	1.0312889165628891
2006	1.0572332918223328
2007	1.0805832295558322
2008	1.1065276048152761
2009	1.1117164798671648
2010	1.1052303860523038
2011	1.0844748858447488
2012	1.0676110419261104
2013	1.050747198007472
2014	1.0533416355334164
2015	1.0403694479036945
2016	1.0429638854296388
2017	1.0286944790369448
2018	1.0286944790369448
2019	1.0286944790369448
2020	1.0286944790369448
2021	1.0286944790369448