Year	% of land area
1961	30.11165387299372
1962	30.074148261673
1963	30.000589136814995
1964	29.65523879540606
1965	29.5115226033541
1966	29.106387321775742
1967	28.975657032758495
1968	28.733903496070624
1969	28.731953536190012
1970	28.367186572991148
1971	27.442200284943073
1972	27.321219795328894
1973	27.13170029033658
1974	27.132701815061843
1975	27.068455319904604
1976	26.955689731861302
1977	26.987144750392726
1978	27.095262516721604
1979	27.07884348395438
1980	27.092202642659988
1981	27.09932754796086
1982	27.114763322276563
1983	26.919080680311176
1984	26.992870438836068
1985	26.965318182912124
1986	26.987393183140345
1987	27.047725984515964
1988	26.841333031254383
1989	26.801996376712367
1990	26.75444383862677
1991	26.502946514598133
1992	26.728620857063767
1993	26.756940955806726
1994	26.541807299461006
1995	26.00189077718805
1996	26.142569372544617
1997	26.05020066734129
1998	25.857254479769168
1999	25.83235583304005
2000	25.770825472119046
2001	24.975119049402885
2002	24.872854122309406
2003	24.730763004818037
2004	24.770435996545217
2005	24.756378797324935
2006	24.46277751578538
2007	24.2608883177824
2008	24.395813108622782
2009	24.25316332725951
2010	24.267620083607063
2011	24.106120010266185
2012	24.318461798489597
2013	24.088727818405356
2014	24.002767975313134
2015	23.929934930696696
2016	23.88015106939345
2017	23.88382502916073
2018	23.60336594517665
2019	23.670230177186532
2020	23.664268616951485
2021	23.631267026733987