Year	% of land area
1961	51.27903823555997
1962	51.38750790924704
1963	51.45982102503842
1964	52.17391304347826
1965	52.36373497243062
1966	52.44508722769592
1967	52.99647473560517
1968	53.15917924613577
1969	54.43369791195878
1970	54.32522823827172
1971	54.31618909879779
1972	54.43369791195878
1973	54.072132333001896
1974	54.578324143541536
1975	53.828075567206
1976	56.02458645936906
1977	56.09689957516044
1978	56.14209527253006
1979	56.09689957516044
1980	55.8709210883124
1981	55.852842809364546
1982	55.87996022778632
1983	55.834764530416706
1984	55.7895688330471
1985	55.762451414625325
1986	55.735333996203565
1987	55.735333996203565
1988	55.69917743830788
1989	55.753412275151405
1990	55.6720600198861
1991	55.69013829883394
1992	55.626864322516504
1993	55.328572719877066
1994	55.6720600198861
1995	55.71725571725572
1996	55.71725571725572
1997	56.06978215673868
1998	51.02594233029015
1999	51.33327307240351
2000	50.45647654343306
2001	49.69718882762361
2002	48.943014705882355
2003	48.96570745610003
2004	49.00698786318499
2005	48.46281296023564
2006	47.776857221761944
2007	47.10431820274376
2008	46.966209372985915
2009	46.33382461311717
2010	46.536477523949884
2011	46.86809137803979
2012	47.19049373618275
2013	46.01142225497421
2014	45.84561532792926
2015	46.16709653647752
2016	46.250921149594696
2017	46.32940309506264
2018	46.33382461311717
2019	46.39830508474576
2020	46.49042004421518
2021	46.48670965364776