Year	% of land area
1961	55.68172671851624
1962	55.65106671103171
1963	55.56228130370169
1964	55.30563339260658
1965	55.14768664227696
1966	55.01965310628609
1967	54.97741780504218
1968	54.6532266027633
1969	54.6867493173066
1970	54.08798716843422
1971	53.26834020244733
1972	53.07164318555403
1973	52.844120207143824
1974	52.68965047986206
1975	52.519504961504566
1976	52.20464247067337
1977	52.1562065105271
1978	52.16592477519195
1979	52.02260021094858
1980	51.87983714495792
1981	51.82337158805072
1982	51.74635869254012
1983	51.317783395215514
1984	51.214913405417335
1985	51.11943487999416
1986	50.99296006665654
1987	50.91843619370564
1988	50.5981412185898
1989	50.565568144944784
1990	50.31925761608255
1991	49.45219144170499
1992	48.68955645311875
1993	48.61736545891446
1994	48.45553723081947
1995	47.84883459404046
1996	47.90095344368831
1997	47.65791330913809
1998	47.64504933671481
1999	47.598116395052
2000	47.36074333589543
2001	46.78510897308732
2002	46.47825347404818
2003	46.07131057697583
2004	45.86111271328457
2005	45.95084098147479
2006	45.42284374439698
2007	45.016679867039514
2008	45.27763188441754
2009	44.942510938110985
2010	44.73504941346016
2011	44.296896204721975
2012	44.147139676092266
2013	43.94496757263541
2014	43.36922877710463
2015	43.305102949669774
2016	43.057712965988806
2017	43.06069693853931
2018	42.84963194573271
2019	43.188034329673336
2020	42.85637943910718
2021	42.76336774442912