Year	% of land area
1961	5.89184826472962
1962	5.89184826472962
1963	5.89184826472962
1964	5.89184826472962
1965	5.89184826472962
1966	5.89184826472962
1967	5.83804143126177
1968	5.83804143126177
1969	5.811138014527845
1970	5.811138014527845
1971	5.811138014527845
1972	5.811138014527845
1973	5.811138014527845
1974	5.824589722894808
1975	5.824589722894808
1976	5.824589722894808
1977	5.83804143126177
1978	5.83804143126177
1979	5.83804143126177
1980	5.851493139628733
1981	5.9187516814635455
1982	6.053268765133172
1983	6.120527306967985
1984	6.187785848802798
1985	6.255044390637611
1986	6.322302932472423
1987	6.3895614743072375
1988	6.456820016142049
1989	6.591337099811676
1990	6.71240247511434
1991	6.71240247511434
1992	6.725854183481301
1993	6.725854183481301
1994	6.725854183481301
1995	6.725854183481301
1996	6.725854183481301
1997	6.860371267150928
1998	6.9948883508205535
1999	7.12940543449018
2000	7.371536185095508
2001	7.371536185095508
2002	7.371536185095508
2003	7.371536185095508
2004	7.371536185095508
2005	7.371536185095508
2006	7.263922518159806
2007	7.263922518159806
2008	7.263922518159806
2009	7.263922518159806
2010	7.652542372881356
2011	7.600215227333871
2012	7.600215227333871
2013	7.600215227333871
2014	7.62277388019428
2015	7.62277388019428
2016	7.62277388019428
2017	7.62277388019428
2018	7.616608250202211
2019	7.616608250202211
2020	7.616608250202211
2021	7.616608250202211