Year	% of land area
1961	0.21345131369581247
1962	0.23285597857724996
1963	0.2522606434586875
1964	0.271665308340125
1965	0.2910699732215625
1966	0.31047463810299997
1967	0.32987930298443746
1968	0.34928396786587496
1969	0.36868863274731245
1970	0.38809329762874994
1971	0.42690262739162493
1972	0.4463072922730625
1973	0.4851166220359375
1974	0.504521286917375
1975	0.5316878177513874
1976	0.566616214537975
1977	0.5976636783482749
1978	0.6287111421585749
1979	0.6287111421585749
1980	0.6287111421585749
1981	0.6287111421585749
1982	0.6287111421585749
1983	0.6287111421585749
1984	0.6287111421585749
1985	0.6287111421585749
1986	0.6287111421585749
1987	0.6287111421585749
1988	0.6287111421585749
1989	0.6287111421585749
1990	0.6287111421585749
1991	0.6287111421585749
1992	0.6403539410874374
1993	0.6403539410874374
1994	0.6403539410874374
1995	0.6597586059688749
1996	0.6597586059688749
1997	0.6597586059688749
1998	0.6597586059688749
1999	0.6597586059688749
2000	0.6597586059688749
2001	0.6597586059688749
2002	0.6597586059688749
2003	0.6597586059688749
2004	0.6597586059688749
2005	0.6597586059688749
2006	0.6597586059688749
2007	0.6597586059688749
2008	0.6597586059688749
2009	0.6597586059688749
2010	0.6597586059688749
2011	0.6597586059688749
2012	0.6597586059688749
2013	0.6597586059688749
2014	0.6597586059688749
2015	0.6597586059688749
2016	0.6597586059688749
2017	0.6597586059688749
2018	0.6597586059688749
2019	0.6597586059688749
2020	0.6597586059688749
2021	0.6597586059688749