Year	% of land area
1961	15.148269424977814
1962	15.163570707225265
1963	15.178871989472716
1964	15.194173271720171
1965	15.194173271720171
1966	15.209474553967622
1967	15.209474553967622
1968	15.209474553967622
1969	15.224775836215073
1970	15.25537840070998
1971	15.25537840070998
1972	15.25537840070998
1973	14.513266211708542
1974	14.52703736573125
1975	14.543868776203444
1976	14.563760443125135
1977	14.612724546316983
1978	14.624965572114942
1979	14.63873672613765
1980	14.647917495486121
1981	14.696881598677969
1982	14.719833522049147
1983	14.709122624475931
1984	14.675459803531535
1985	14.678520059981025
1986	14.683110444655261
1987	14.649447623710868
1988	14.615784802766472
1989	14.59436300762004
1990	14.63873672613765
1991	14.618845059215962
1992	14.588242494721056
1993	14.657098264834593
1994	14.588242494721056
1995	14.597423264069528
1996	14.602013648743764
1997	14.626495700339689
1998	14.621905315665455
1999	14.826942497781314
2000	15.162040579000521
2001	15.285980965204885
2002	15.090124552437494
2003	15.073293141965296
2004	15.169416301919133
2005	15.395800171421575
2006	15.817099484291553
2007	16.184661525278493
2008	16.368951952365645
2009	16.522271544466555
2010	16.549306554817377
2011	16.510278742977853
2012	16.460231187322975
2013	16.494150793164696
2014	16.561523856189133
2015	16.740674802474427
2016	16.771347161371366
2017	16.946150900038297
2018	16.9760992799142
2019	16.838363719932588
2020	16.83852482878024
2021	16.83852482878024