Year	% of land area
1961	0.7785834881997837
1962	0.7785834881997837
1963	0.7785834881997837
1964	0.7834420435083627
1965	0.7834420435083627
1966	0.7834420435083627
1967	0.787085959989797
1968	0.787085959989797
1969	0.787085959989797
1970	0.7895152376440865
1971	0.791944515298376
1972	0.791944515298376
1973	0.791944515298376
1974	0.791944515298376
1975	0.791944515298376
1976	0.7943737929526654
1977	0.7943737929526654
1978	0.7955884317798102
1979	0.7955884317798102
1980	0.7955884317798102
1981	0.7955884317798102
1982	0.7955884317798102
1983	0.801661625915534
1984	0.801661625915534
1985	0.801661625915534
1986	0.801661625915534
1987	0.801661625915534
1988	0.801661625915534
1989	0.801661625915534
1990	0.801661625915534
1991	0.801661625915534
1992	0.801661625915534
1993	0.8478179013470345
1994	0.9073352038771271
1995	0.9911452829501147
1996	0.9911452829501147
1997	0.9911452829501147
1998	0.9911452829501147
1999	0.9911452829501147
2000	0.9911452829501147
2001	0.9911452829501147
2002	0.9911452829501147
2003	0.98993064412297
2004	0.98993064412297
2005	0.9887160052958253
2006	0.9875013664686806
2007	0.9717110617157989
2008	0.9717110617157989
2009	0.9717110617157989
2010	0.9717110617157989
2011	0.9717110617157989
2012	0.9717110617157989
2013	0.9717110617157989
2014	0.9717110617157989
2015	0.9717110617157989
2016	0.9717110617157989
2017	0.9717110617157989
2018	0.9717110617157989
2019	0.9717110617157989
2020	0.9717110617157989
2021	0.9717110617157989