Year	% of land area
1961	0.6427534729421522
1962	0.6738544474393532
1963	0.7256894049346879
1964	0.8293593199253577
1965	0.9641302094132282
1966	1.098901098901099
1967	1.2025710138917687
1968	1.5032137673647108
1969	1.6068836823553805
1970	1.5032137673647108
1971	1.420277835372175
1972	1.430644826871242
1973	1.5135807588637777
1974	1.6898196143479163
1975	1.8556914783329876
1976	1.8453244868339207
1977	1.700186605846983
1978	1.482479784366577
1979	1.430644826871242
1980	1.409910843873108
1981	1.420277835372175
1982	1.358075886377773
1983	1.399543852374041
1984	1.409910843873108
1985	1.399543852374041
1986	1.420277835372175
1987	1.409910843873108
1988	1.4617458013684428
1989	1.5446817333609788
1990	1.6172506738544474
1991	1.700186605846983
1992	1.783122537839519
1993	1.8660584698320548
1994	1.9489944018245904
1995	2.094132282811528
1996	2.073398299813394
1997	2.094132282811528
1998	2.094132282811528
1999	2.073398299813394
2000	2.073398299813394
2001	2.067397146991937
2002	1.9526810620931916
2003	1.9318181818181817
2004	1.8901053501342697
2005	1.8688693856479093
2006	1.8682906688687038
2007	1.9087907552620718
2008	2.000206206825446
2009	2.070883989284978
2010	2.139917695473251
2011	2.1607161230579277
2012	2.1354434282190935
2013	2.2088559522098823
2014	2.206712511546751
2015	2.2012417261019035
2016	2.2874375570577192
2017	2.297200287150036
2018	2.276456111566858
2019	2.223360655737705
2020	2.1823770491803276
2021	2.0901639344262297