Year	% of land area
1961	7.028704422032583
1962	6.5089216446858025
1963	6.5089216446858025
1964	6.570985259891389
1965	6.69511249030256
1966	6.6408068269976726
1967	6.625290923196276
1968	6.602017067494181
1969	6.881303335919317
1970	6.982156710628394
1971	7.12955779674166
1972	7.17610550814585
1973	7.2614429790535295
1974	7.315748642358417
1975	7.439875872769589
1976	7.556245151280063
1977	7.672614429790535
1978	7.734678044996121
1979	7.734678044996121
1980	7.928626842513577
1981	7.959658650116369
1982	7.936384794414275
1983	7.967416602017067
1984	8.006206361520558
1985	8.060512024825446
1986	8.114817688130334
1987	8.161365399534523
1988	8.231186966640806
1989	8.277734678044995
1990	8.285492629945693
1991	8.355314197051978
1992	8.363072148952677
1993	8.38634600465477
1994	8.409619860356866
1995	8.401861908456167
1996	8.448409619860357
1997	8.502715283165244
1998	8.518231186966641
1999	8.595810705973623
2000	8.634600465477114
2001	8.782001551590382
2002	8.758727695888286
2003	8.782001551590382
2004	8.782001551590382
2005	8.813033359193174
2006	8.82854926299457
2007	8.797517455391777
2008	8.82854926299457
2009	8.836307214895267
2010	8.820791311093872
2011	8.906128782001552
2012	8.813033359193174
2013	8.719937936384795
2014	8.56477889837083
2015	8.619084561675718
2016	8.642358417377812
2017	8.39943910007758
2018	8.418191621411946
2019	8.442433669511248
2020	8.442433669511248
2021	8.442433669511248