Year	% of land area
1961	85.34883720930233
1962	85.93023255813954
1963	85.69767441860465
1964	85.87209302325581
1965	86.27906976744187
1966	86.80232558139535
1967	87.03488372093024
1968	87.09302325581395
1969	86.86046511627907
1970	86.86046511627907
1971	86.86046511627907
1972	87.96511627906976
1973	87.96511627906976
1974	86.16279069767442
1975	76.33720930232558
1976	79.7093023255814
1977	80.98837209302326
1978	80.98837209302326
1979	77.90697674418605
1980	75.05813953488372
1981	74.65116279069768
1982	74.76744186046511
1983	74.88372093023256
1984	73.77906976744187
1985	74.65116279069768
1986	77.26744186046511
1987	75.98837209302326
1988	74.70930232558139
1989	73.48837209302326
1990	71.97674418604652
1991	71.33720930232558
1992	71.1046511627907
1993	71.04651162790697
1994	71.04651162790697
1995	71.04651162790697
1996	71.04651162790697
1997	71.1046511627907
1998	71.1046511627907
1999	71.1046511627907
2000	71.1046511627907
2001	71.16279069767441
2002	71.16279069767441
2003	71.16279069767441
2004	71.16279069767441
2005	71.16279069767441
2006	71.1046511627907
2007	71.1046511627907
2008	71.1046511627907
2009	71.16279069767441
2010	70.99088953488373
2011	70.98837209302326
2012	70.93023255813954
2013	70.8573546511628
2014	70.69767441860465
2015	70.46511627906978
2016	70.23255813953489
2017	70
2018	69.82558139534883
2019	69.59302325581396
2020	69.47674418604652
2021	69.47674418604652