Year	% of land area
1961	70.175
1962	69.325
1963	68.60000000000001
1964	68.15
1965	67.325
1966	67.15
1967	67.125
1968	67.35
1969	66.95
1970	66.525
1971	66.175
1972	66.27499999999999
1973	66.325
1974	66.025
1975	66.25
1976	66.425
1977	65.925
1978	66.07499999999999
1979	66.05
1980	65.975
1981	65.925
1982	65.75
1983	64.825
1984	65.3
1985	65.025
1986	64.85
1987	64.45
1988	64
1989	63.625
1990	64.025
1991	63.7
1992	63.475
1993	63.324999999999996
1994	59.12500000000001
1995	57.975
1996	58.050000000000004
1997	59.12500000000001
1998	59.150000000000006
1999	57.35
2000	57.025000000000006
2001	57.3
2002	56.89999999999999
2003	56.65
2004	56.725
2005	58.3
2006	58.675
2007	57.65
2008	60.050000000000004
2009	60.775
2010	60.525
2011	62.475
2012	60.45
2013	60.19
2014	60.8
2015	58.791275
2016	59.262499999999996
2017	59.185
2018	59.709999999999994
2019	59.898300000000006
2020	59.27325
2021	58.925000000000004