Year	% of land area
1961	1.694915254237288
1962	1.694915254237288
1963	1.694915254237288
1964	1.6142050040355123
1965	1.6142050040355123
1966	1.6142050040355123
1967	1.5469464622006994
1968	1.5469464622006994
1969	1.5469464622006994
1970	1.4931396287328491
1971	1.4931396287328491
1972	1.4931396287328491
1973	1.4931396287328491
1974	1.5065913370998116
1975	1.5200430454667744
1976	1.533494753833737
1977	1.5469464622006994
1978	1.5603981705676622
1979	1.5873015873015872
1980	1.6142050040355123
1981	1.6411084207694377
1982	1.668011837503363
1983	1.694915254237288
1984	1.694915254237288
1985	1.7487220877051384
1986	1.8159806295399514
1987	1.8832391713747645
1988	1.9504977132095775
1989	2.0177562550443904
1990	2.0850147968792037
1991	2.0850147968792037
1992	2.1522733387140165
1993	2.1522733387140165
1994	2.2195318805488298
1995	2.0850147968792037
1996	2.0850147968792037
1997	2.0581113801452786
1998	2.044659671778316
1999	2.0177562550443904
2000	1.977401129943503
2001	2.1522733387140165
2002	2.1522733387140165
2003	2.1522733387140165
2004	2.1522733387140165
2005	2.1522733387140165
2006	2.2195318805488298
2007	2.354048964218456
2008	2.354048964218456
2009	2.4213075060532687
2010	2.535647027172451
2011	2.5423728813559325
2012	2.4078557976863064
2013	2.2733387140166803
2014	2.1451699946033456
2015	2.0102536427415005
2016	1.8753372908796546
2017	1.7404209390178087
2018	1.6042059854408197
2019	1.4602453491507146
2020	1.3494203289296305
2021	1.4466972229711512