Year	% of land area
1961	25.75566060677322
1962	25.748890771378203
1963	25.77579195939524
1964	25.785055944672628
1965	25.809641136370317
1966	25.811957132689663
1967	25.87199488342967
1968	25.90379529442994
1969	25.968910421716206
1970	26.04026092370841
1971	26.235428152004182
1972	26.421242318241053
1973	26.47015070954363
1974	26.4870753583349
1975	26.405569812840106
1976	26.436835874554504
1977	26.431847557016024
1978	26.407974894510446
1979	26.515134644488846
1980	26.41385398303794
1981	26.090646637384054
1982	26.167051628195754
1983	26.25081973200264
1984	26.775360918135473
1985	27.271114167445347
1986	27.73547308401841
1987	28.253830537945507
1988	28.787936822958375
1989	29.210589841825797
1990	29.68576271820549
1991	29.87440129054901
1992	30.04533838102661
1993	30.77409464424897
1994	31.442644658723975
1995	32.073625003897114
1996	32.73560097984634
1997	33.2750520610177
1998	34.07284868054782
1999	34.58979621868389
2000	34.54107231711391
2001	34.60534006458078
2002	34.66582100879635
2003	34.74057055585793
2004	34.81569471390675
2005	33.3220517866003
2006	33.35795241102677
2007	33.39640828779234
2008	33.182763865827674
2009	33.144173241325234
2010	33.17759778866788
2011	33.19408623596234
2012	33.20924767789445
2013	33.23164252051373
2014	33.22893530169587
2015	33.245967437342884
2016	33.29657688597021
2017	33.39352779495643
2018	33.391709068495224
2019	33.32467283219206
2020	33.406060394533064
2021	33.40621704255942