Year	% of land area
1961	11.72899130674762
1962	11.805651380647932
1963	11.882311454548242
1964	11.958971528448552
1965	11.958971528448552
1966	12.01263358017877
1967	12.026432393480828
1968	12.026432393480828
1969	12.050963617128927
1970	12.06629563190899
1971	12.112291676249177
1972	12.127623691029237
1973	12.127623691029237
1974	12.127623691029237
1975	12.127623691029237
1976	12.127623691029237
1977	12.127623691029237
1978	12.127623691029237
1979	12.127623691029237
1980	12.127623691029237
1981	12.127623691029237
1982	12.127623691029237
1983	12.127623691029237
1984	12.127623691029237
1985	12.127623691029237
1986	12.127623691029237
1987	12.127623691029237
1988	12.127623691029237
1989	12.127623691029237
1990	12.127623691029237
1991	12.127623691029237
1992	12.127623691029237
1993	11.995768363920703
1994	11.81025098508195
1995	11.733590911181638
1996	11.724391702313602
1997	11.782653358477837
1998	11.893043864894286
1999	11.733590911181638
2000	11.779586955521825
2001	11.779586955521825
2002	11.771920948131793
2003	11.91604188706438
2004	11.983502752096653
2005	11.966637535838585
2006	11.949772319580516
2007	11.949772319580516
2008	11.949772319580516
2009	11.94823911810251
2010	11.94823911810251
2011	11.945172715146498
2012	11.943639513668492
2013	11.93597350627846
2014	11.914508685586373
2015	11.905309476718335
2016	11.850114223510111
2017	11.804118179169924
2018	11.949772319580516
2019	11.940573110712478
2020	12.003434371310734
2021	12.003434371310734