Year	% of land area
1961	7.471213852509449
1962	7.471213852509449
1963	7.471213852509449
1964	7.471213852509449
1965	7.471213852509449
1966	7.471213852509449
1967	7.471213852509449
1968	7.471213852509449
1969	7.471213852509449
1970	7.471213852509449
1971	7.471213852509449
1972	7.471213852509449
1973	7.471213852509449
1974	7.471213852509449
1975	7.910697020304122
1976	7.910697020304122
1977	7.910697020304122
1978	8.350180188098797
1979	8.350180188098797
1980	8.350180188098797
1981	8.350180188098797
1982	9.229146523688144
1983	9.229146523688144
1984	10.108112859277488
1985	10.547596027072164
1986	10.547596027072164
1987	10.987079194866837
1988	11.42656236266151
1989	11.42656236266151
1990	11.866045530456184
1991	12.305528698250857
1992	12.305528698250857
1993	12.305528698250857
1994	12.305528698250857
1995	13.184495033840204
1996	14.06346136942955
1997	15.821394040608244
1998	16.033473235475082
1999	16.245552430341917
2000	16.457632064691925
2001	16.66971125955876
2002	16.881790454425598
2003	17.093869649292433
2004	17.305949283642438
2005	17.518028478509272
2006	17.73010767337611
2007	17.942186868242946
2008	18.154266063109784
2009	18.36634569745979
2010	18.578424892326623
2011	18.79050408719346
2012	19.002583282060296
2013	19.21466247692713
2014	19.42674211127714
2015	19.638821306143978
2016	19.850900501010813
2017	20.06297969587765
2018	20.275059330227652
2019	20.48713852509449
2020	20.69985452659614
2021	20.69545955971222