Year	% of land area
1961	3.1834159531320414
1962	3.1834159531320414
1963	3.199639477242001
1964	3.199639477242001
1965	3.2086525461919786
1966	3.2176656151419554
1967	3.2176656151419554
1968	3.2176656151419554
1969	3.2194682289319516
1970	3.2194682289319516
1971	3.220369535826949
1972	3.233889139251915
1973	3.2483100495718795
1974	3.2618296529968456
1975	3.2762505633168093
1976	3.2897701667417754
1977	3.3041910770617395
1978	3.317710680486706
1979	3.3321315908066698
1980	3.345651194231636
1981	3.3600721045516
1982	3.3735917079765665
1983	3.3880126182965298
1984	3.4015322217214963
1985	3.4159531320414604
1986	3.429472735466426
1987	3.4465975664713837
1988	3.2798557908968005
1989	3.1293375394321767
1990	2.978819287967553
1991	2.7381703470031544
1992	2.7670121676430823
1993	2.6345200540784135
1994	2.5525011266336186
1995	2.1622352410995944
1996	2.1928796755295177
1997	2.288418206399279
1998	2.299233889139252
1999	2.2857142857142856
2000	2.5398828301036502
2001	2.1937809824245154
2002	1.992789544840018
2003	2.0405588102748986
2004	2.017124831004957
2005	1.8260477692654349
2006	1.7166291122127082
2007	1.800811176205498
2008	1.6493916178458765
2009	1.5998197386210005
2010	1.5890040558810274
2011	1.4294727354664263
2012	1.390716538981523
2013	1.2825597115817937
2014	1.348355114916629
2015	1.3645786390265886
2016	1.4736367733213158
2017	1.605227579990987
2018	1.883058584948175
2019	1.90400180261379
2020	1.8413699864803967
2021	1.7963046417305093