Year	% of land area
1961	7.45627886447326
1962	7.501098239404921
1963	7.494809650914022
1964	7.540995290496346
1965	7.580464760577301
1966	7.630822009092203
1967	7.633487310376382
1968	7.704820306896188
1969	7.608789345331586
1970	7.557941280233962
1971	7.439368511610292
1972	7.460101188179664
1973	7.3697965962056875
1974	7.4203265766585815
1975	7.327262715834316
1976	7.389314979711994
1977	7.438953554389102
1978	7.527177956956701
1979	7.558052699845108
1980	7.586199032998138
1981	7.642870214867259
1982	7.910301340952747
1983	8.137546504023025
1984	8.517836821714832
1985	8.814816559947431
1986	8.859240203104546
1987	8.862465847921651
1988	8.836709365249304
1989	8.853594762691195
1990	8.867077664411607
1991	8.832655526084585
1992	8.70047246703694
1993	8.66381870378108
1994	8.623048503208974
1995	8.53485956493389
1996	8.649672579534347
1997	8.73595071610561
1998	8.773343313419875
1999	8.88844324721104
2000	8.939508549375617
2001	9.043142238466196
2002	9.064558078943387
2003	9.078807919032679
2004	9.22518162816544
2005	9.263784992843556
2006	9.203433224122477
2007	9.169302636922913
2008	9.22853612575726
2009	9.362643312947913
2010	9.25094249242517
2011	9.448525635980772
2012	9.398425960878331
2013	9.341145468629584
2014	9.333183542178048
2015	9.30051077176878
2016	9.253168472158848
2017	9.261453448742518
2018	9.209531343051305
2019	9.123668920896316
2020	9.122411304578826
2021	9.148669351105436