Year	% of land area
1961	54.24464615832
1962	54.36235105138165
1963	54.83940205914325
1964	54.81309155363535
1965	54.74177623607447
1966	54.911409758428015
1967	54.742468617798366
1968	55.024267979422405
1969	55.6848001440154
1970	55.31506830345706
1971	55.36699693274896
1972	55.62317817058901
1973	55.49093326132564
1974	55.16482146937249
1975	54.81378393535924
1976	54.926642156353644
1977	55.01872892563128
1978	55.006958436325114
1979	55.54978570785646
1980	55.2859882710536
1981	55.22852058797056
1982	54.24187663142444
1983	53.91230293085184
1984	54.579758912683744
1985	54.93702788221202
1986	55.16689861454417
1987	55.85166413947337
1988	55.71664970331443
1989	55.94124575625303
1990	55.78812443705397
1991	56.05198800063738
1992	29.27601733844816
1993	29.158277179720127
1994	29.130745376022734
1995	28.865711797302804
1996	28.75607577013229
1997	28.84619923775994
1998	28.784962756843647
1999	28.753994601335073
2000	28.74308338728575
2001	28.676199883256928
2002	28.57228115551983
2003	28.46711657860708
2004	28.403160769866417
2005	28.338970557203076
2006	28.32447910582852
2007	28.195124001249805
2008	28.151178134328067
2009	28.112514884086526
2010	28.353812003226096
2011	28.303583054916867
2012	28.283052672754756
2013	28.278714721404054
2014	28.279990750004515
2015	28.251301785688263
2016	28.227140877467953
2017	28.20258730489052
2018	28.172669801898195
2019	28.097211329315506
2020	28.08302461396835
2021	28.073816680641503