Year	% of land area
1961	7.031730684714775
1962	7.031730684714775
1963	7.031730684714775
1964	7.031730684714775
1965	7.031730684714775
1966	7.031730684714775
1967	7.031730684714775
1968	7.031730684714775
1969	7.031730684714775
1970	7.031730684714775
1971	7.031730684714775
1972	7.031730684714775
1973	7.031730684714775
1974	7.031730684714775
1975	7.031730684714775
1976	7.031730684714775
1977	7.031730684714775
1978	7.031730684714775
1979	7.031730684714775
1980	7.031730684714775
1981	7.031730684714775
1982	6.996572031291201
1983	6.961413377867627
1984	6.926254724444053
1985	6.89109607102048
1986	6.855937417596906
1987	6.820778764173332
1988	6.7856201107497585
1989	6.7504614573261845
1990	6.715302803902611
1991	6.680144150479037
1992	6.680144150479037
1993	7.031730684714775
1994	7.471213852509449
1995	7.471213852509449
1996	7.471213852509449
1997	7.471213852509449
1998	7.663745715039114
1999	7.856277577568779
2000	8.048809440098445
2001	8.24134130262811
2002	8.433873165157776
2003	8.62640502768744
2004	8.818936890217104
2005	9.01146875274677
2006	9.204000615276435
2007	9.3965324778061
2008	9.589064340335767
2009	9.781595763382262
2010	9.974127625911928
2011	10.166659488441592
2012	10.359191350971257
2013	10.551723213500923
2014	10.744255076030587
2015	10.936786938560253
2016	11.12931880108992
2017	11.321850663619584
2018	11.514382526149248
2019	11.706914388678912
2020	11.899812334914056
2021	11.904207301797982