Year	% of land area
1961	60.2322206095791
1962	60.41364296081277
1963	60.59506531204645
1964	60.77648766328012
1965	60.957910014513786
1966	61.13933236574746
1967	61.32075471698113
1968	61.502177068214806
1969	61.68359941944848
1970	61.86502177068215
1971	62.046444121915826
1972	57.47460087082729
1973	57.43831640058055
1974	57.43831640058055
1975	57.43831640058055
1976	57.51088534107402
1977	57.51088534107402
1978	57.87373004354136
1979	57.87373004354136
1980	58.055152394775035
1981	58.055152394775035
1982	58.055152394775035
1983	58.055152394775035
1984	58.055152394775035
1985	58.055152394775035
1986	58.055152394775035
1987	58.055152394775035
1988	58.01886792452831
1989	57.98258345428157
1990	57.94629898403484
1991	57.9100145137881
1992	57.14804063860668
1993	57.14804063860668
1994	57.87373004354136
1995	57.692307692307686
1996	57.692307692307686
1997	61.32075471698113
1998	61.32075471698113
1999	61.32075471698113
2000	61.32075471698113
2001	60.59506531204645
2002	60.59506531204645
2003	60.59506531204645
2004	60.59506531204645
2005	64.22351233671988
2006	64.22351233671988
2007	64.22351233671988
2008	64.22351233671988
2009	65.90457184325109
2010	71.98838896952104
2011	72.8955007256894
2012	73.43976777939042
2013	75.03628447024674
2014	75.03628447024674
2015	75.03628447024674
2016	75.03628447024674
2017	72.93178519593614
2018	72.38751814223512
2019	64.94920174165458
2020	64.94920174165458
2021	65.13062409288824