Year	% of land area
1961	55.49508778964856
1962	55.546644516369255
1963	55.57242287972961
1964	55.732821585082924
1965	55.950505542348125
1966	55.94191275456134
1967	55.60106550568557
1968	55.23730415604503
1969	55.14851201558159
1970	54.4868673559992
1971	54.28350471171197
1972	54.27491192392518
1973	54.12597026895426
1974	53.90828631168906
1975	53.82522269641681
1976	53.72783776816659
1977	53.587488900982436
1978	53.4442757712027
1979	53.25809870248904
1980	53.043279007819436
1981	52.877151777274946
1982	52.69097470856128
1983	52.50193337725203
1984	52.37017729785467
1985	52.255606794030875
1986	52.152493340589466
1987	51.9147595451551
1988	51.83456019247845
1989	51.71712542605906
1990	51.64838312376479
1991	49.08200383811187
1992	48.55211525792685
1993	49.157882676443634
1994	49.57749706396265
1995	49.679175021483815
1996	49.66341058179839
1997	49.640452657212435
1998	49.77651710503696
1999	49.148948363803086
2000	48.91245164063619
2001	48.82201203783319
2002	48.63555581035372
2003	48.74000172013417
2004	48.779998279668554
2005	48.833008372519785
2006	48.59486120669879
2007	48.613301976080535
2008	48.53569687060781
2009	48.43808267117983
2010	47.91003241816565
2011	47.965916915308696
2012	47.8108681930338
2013	47.85886264618207
2014	47.936371453138435
2015	47.95906667431061
2016	47.68433707350584
2017	47.76311646678307
2018	47.64153643597229
2019	47.700277626720855
2020	47.49706631557858
2021	47.485617791007186