Year	% of land area
1961	2.772963604852686
1962	2.772963604852686
1963	2.772963604852686
1964	2.772963604852686
1965	2.772963604852686
1966	2.8162911611785093
1967	2.8162911611785093
1968	2.8509532062391685
1969	2.859618717504333
1970	2.8812824956672443
1971	2.902946273830156
1972	3.032928942807626
1973	3.119584055459272
1974	3.2062391681109186
1975	3.2495667244367423
1976	3.2928942807625647
1977	3.3362218370883885
1978	3.3578856152513
1979	3.3795493934142113
1980	3.3795493934142113
1981	3.3795493934142113
1982	3.401213171577123
1983	3.401213171577123
1984	3.422876949740035
1985	3.431542461005199
1986	3.4358752166377813
1987	3.4358752166377813
1988	3.4445407279029463
1989	3.4445407279029463
1990	3.4618717504332754
1991	3.4618717504332754
1992	3.4618717504332754
1993	3.4618717504332754
1994	3.561525129982669
1995	3.587521663778163
1996	3.5701906412478337
1997	3.7001733102253036
1998	3.734835355285962
1999	3.799826689774697
2000	3.9861351819757362
2001	4.202772963604852
2002	4.397746967071057
2003	4.592720970537262
2004	4.787694974003466
2005	4.982668977469671
2006	5.1993067590987865
2007	5.37261698440208
2008	5.589254766031196
2009	5.892547660311958
2010	6.065857885615252
2011	6.1871750433275565
2012	6.339038128249566
2013	6.490901213171576
2014	6.50953206239168
2015	6.528162911611784
2016	6.546793760831888
2017	6.235701906412478
2018	5.924610051993068
2019	5.613518197573657
2020	5.303292894280762
2021	5.303292894280762