Year	% of land area
1961	56.44419930134216
1962	56.44419930134216
1963	56.44419930134216
1964	56.44419930134216
1965	56.53612796469939
1966	56.53612796469939
1967	56.53612796469939
1968	56.53612796469939
1969	56.53612796469939
1970	56.53612796469939
1971	52.950910093767234
1972	52.950910093767234
1973	52.950910093767234
1974	52.950910093767234
1975	52.950910093767234
1976	52.950910093767234
1977	52.950910093767234
1978	54.78948336091193
1979	55.70876999448428
1980	55.80069865784152
1981	55.80069865784152
1982	55.80069865784152
1983	55.80069865784152
1984	56.71998529141386
1985	56.8119139547711
1986	56.8119139547711
1987	57.17962860820004
1988	57.73120058834345
1989	57.73120058834345
1990	58.09891524177239
1991	58.55855855855856
1992	58.9262732119875
1993	59.38591652877368
1994	59.75363118220262
1995	60.121345835631544
1996	60.489060489060485
1997	61.224489795918366
1998	61.59220444934731
1999	61.959919102776254
2000	62.511491082919655
2001	62.879205736348595
2002	63.24692038977753
2003	63.61463504320647
2004	63.98234969663541
2005	64.71777900349329
2006	65.63706563706563
2007	66.09670895385182
2008	66.8321382607097
2009	67.19985291413863
2010	67.3837102408531
2011	67.3837102408531
2012	70.78507078507079
2013	70.23349880492738
2014	70.23349880492738
2015	70.23349880492738
2016	70.23349880492738
2017	70.23349880492738
2018	70.23349880492738
2019	70.23349880492738
2020	70.23349880492738
2021	70.23349880492738