Year	% of land area
1961	69.14899713467048
1962	69.14899713467048
1963	69.14899713467048
1964	69.14899713467048
1965	69.14899713467048
1966	69.14899713467048
1967	69.14899713467048
1968	69.14899713467048
1969	69.14899713467048
1970	69.14899713467048
1971	69.14899713467048
1972	69.14899713467048
1973	69.14899713467048
1974	69.14899713467048
1975	69.14899713467048
1976	69.14899713467048
1977	69.14899713467048
1978	69.14899713467048
1979	69.14899713467048
1980	69.14899713467048
1981	69.14899713467048
1982	69.14899713467048
1983	69.14899713467048
1984	69.14899713467048
1985	69.14899713467048
1986	69.14899713467048
1987	69.14899713467048
1988	69.14899713467048
1989	69.14899713467048
1990	69.14899713467048
1991	69.14899713467048
1992	69.14899713467048
1993	69.14899713467048
1994	69.14899713467048
1995	69.14326647564471
1996	69.12679083094557
1997	69.12679083094557
1998	69.12106017191977
1999	69.12106017191977
2000	69.12106017191977
2001	69.12106017191977
2002	69.15401146131805
2003	69.15401146131805
2004	69.15401146131805
2005	69.15401146131805
2006	69.15401146131805
2007	69.15401146131805
2008	69.15401146131805
2009	69.06160458452723
2010	69.05085959885386
2011	69.05659025787966
2012	69.05659025787966
2013	69.05659025787966
2014	69.067335243553
2015	69.067335243553
2016	69.01862464183381
2017	69.01862464183381
2018	69.00787965616045
2019	69.00787965616045
2020	70.3294289897511
2021	70.12408759124088