Year	% of land area
1961	6.509799355765127
1962	6.568013350409438
1963	6.626227345053751
1964	6.684441339698063
1965	6.742655334342376
1966	6.800869328986689
1967	6.859083323631
1968	6.917297318275313
1969	6.975511312919626
1970	7.033725307563938
1971	7.111343967089688
1972	7.169557961734001
1973	7.24717662125975
1974	7.305390615904063
1975	7.379128342453526
1976	7.514960996623589
1977	7.604222455078201
1978	7.689602980556526
1979	7.697364846509101
1980	7.705126712461675
1981	7.712888578414251
1982	7.720650444366826
1983	7.728412310319401
1984	7.736174176271976
1985	7.74393604222455
1986	7.751697908177126
1987	7.759459774129701
1988	7.767221640082275
1989	7.774983506034851
1990	7.782745371987426
1991	7.806659680987309
1992	7.830573989987193
1993	7.854488298987077
1994	7.878402607986961
1995	7.902316916986845
1996	7.926231225986727
1997	7.950145534986611
1998	7.9740598439864945
1999	7.997974152986378
2000	8.021888461986261
2001	8.0415221019133
2002	8.061155741840338
2003	8.080789381767376
2004	8.100423021694416
2005	8.120056661621454
2006	8.139690301548493
2007	8.159323941475531
2008	8.17895758140257
2009	8.198591221329607
2010	8.218224861256646
2011	8.264338106880894
2012	8.310451352505142
2013	8.35656459812939
2014	8.35656459812939
2015	8.35656459812939
2016	8.35656459812939
2017	8.35656459812939
2018	8.35656459812939
2019	8.35656459812939
2020	8.35656459812939
2021	8.35656459812939