Year	% of land area
1961	43.7622061184645
1962	43.986368609892295
1963	44.24192418454651
1964	44.497677114283206
1965	44.84633084906025
1966	45.03816967519101
1967	45.31241762127934
1968	46.456107978674645
1969	46.52714784808706
1970	46.025348954932156
1971	46.42606573681935
1972	46.68756427717772
1973	46.86530287573992
1974	47.28833624455554
1975	47.49516740151578
1976	47.22179334357618
1977	47.14249040426981
1978	47.611560138226814
1979	47.65669961583951
1980	47.971004235494874
1981	48.23025025183331
1982	48.43014886448889
1983	48.59717755993826
1984	49.14351973384236
1985	49.78013539540854
1986	49.3808394815406
1987	49.85049517325935
1988	50.19552802916688
1989	50.29008442127262
1990	50.46661209650269
1991	50.505396679817444
1992	50.64082642424261
1993	50.39715301992106
1994	50.932287765874335
1995	50.72922215242983
1996	50.8269109222445
1997	51.16666061644839
1998	51.26212116454157
1999	50.98588457533384
2000	51.03742699422805
2001	51.15097821612891
2002	50.873062167773845
2003	49.98976613471679
2004	48.25265625414679
2005	48.91541491508823
2006	48.985685548225334
2007	48.63782937407589
2008	48.32934507758503
2009	48.19371317847886
2010	47.871111552424416
2011	48.7025691716092
2012	48.316584621764484
2013	47.693655513646284
2014	47.776032130092645
2015	46.752263888471994
2016	46.54873309269708
2017	47.87088415432068
2018	47.325934810457504
2019	47.45284976850251
2020	47.16158173784971
2021	47.47085115304753