Year	% of land area
1961	5.532787834164548
1962	5.5220214032016814
1963	5.5351031956619385
1964	5.566129039726973
1965	5.606647865931308
1966	5.580252744861055
1967	5.601322534487309
1968	5.57909506411236
1969	5.592061088497747
1970	5.61104705277635
1971	5.683170563420067
1972	5.8042639697335945
1973	5.879308907700002
1974	5.853376738844537
1975	5.781831737270084
1976	5.765392594513494
1977	5.691532220719803
1978	5.618829533035731
1979	5.715264785966992
1980	5.437883194102284
1981	5.5284837090410655
1982	5.603934743549373
1983	5.58094309741234
1984	5.639941096930743
1985	5.671712634523126
1986	5.710842425028248
1987	5.765392594513494
1988	5.775001389223331
1989	5.748004149147017
1990	5.7591642432437435
1991	5.985978105840295
1992	6.099614258988275
1993	6.21505871783948
1994	6.145768888806565
1995	6.138283290421768
1996	6.118077037064478
1997	6.012433548817308
1998	6.028027580713876
1999	5.952127363995036
2000	5.735176987052439
2001	5.799544334747254
2002	5.827097264156186
2003	5.899431910930303
2004	5.84672326345756
2005	5.805786487390755
2006	5.84922960440021
2007	5.87847803486544
2008	5.618422789188889
2009	5.588209749087174
2010	5.593867468958665
2011	5.594319105620444
2012	5.619633919534559
2013	5.603189227925014
2014	5.54260719197579
2015	5.5514063755599405
2016	5.615267857153197
2017	5.72373952187376
2018	5.726280162186925
2019	5.643382683826056
2020	5.7788279699328635
2021	5.736473792543896