Year	% of land area
1961	0.7040389603514902
1962	0.7040389603514902
1963	0.7040389603514902
1964	0.7040389603514902
1965	0.7058034690240502
1966	0.7058034690240502
1967	0.7058034690240502
1968	0.7058034690240502
1969	0.7058034690240502
1970	0.7058034690240502
1971	0.7058034690240502
1972	0.7075679776966104
1973	0.7075679776966104
1974	0.7075679776966104
1975	0.7075679776966104
1976	0.7075679776966104
1977	0.7075679776966104
1978	0.7075679776966104
1979	0.7110969950417306
1980	0.7110969950417306
1981	0.7110969950417306
1982	0.7146260123868509
1983	0.7146260123868509
1984	0.7146260123868509
1985	0.7181550297319711
1986	0.7181550297319711
1987	0.7216840470770914
1988	0.7216840470770914
1989	0.730506590439892
1990	0.7410936424752528
1991	0.5293526017680377
1992	0.44112716814003144
1993	0.617578035396044
1994	0.6969809256612497
1995	0.6087554920332434
1996	0.6087554920332434
1997	0.5293526017680377
1998	0.40583699468882894
1999	0.42348208141443017
2000	0.617578035396044
2001	0.3529017345120251
2002	0.43230462477723075
2003	0.3440791911492245
2004	0.3987789599985884
2005	0.3767226015915868
2006	0.35466624318458523
2007	0.32114057840594284
2008	0.492297919644275
2009	0.5575847405289996
2010	0.4570077461930725
2011	0.5717008099094807
2012	0.5028849716796358
2013	0.49406242831683517
2014	0.7093324863691705
2015	0.45806645139660856
2016	0.45806645139660856
2017	0.45806645139660856
2018	0.45806645139660856
2019	0.45877225486563267
2020	0.45877225486563267
2021	0.45877225486563267