Year	% of land area
1961	27.47568170945623
1962	27.220538988996974
1963	32.849625259129326
1964	33.53532132036358
1965	34.380481581884865
1966	35.16185616329134
1967	35.95917716472652
1968	37.01164088662095
1969	37.12326582682188
1970	37.202997926965395
1971	37.298676447137616
1972	37.39435496730984
1973	37.49003348748206
1974	37.58571200765428
1975	37.61760484771169
1976	38.20762238877372
1977	38.79763992983575
1978	39.37171105086908
1979	37.61760484771169
1980	37.458140647424656
1981	37.458140647424656
1982	36.61298038590336
1983	36.804337426247805
1984	36.85217668633392
1985	36.91596236644873
1986	37.09137298676447
1987	37.2189443469941
1988	37.266783607080214
1989	37.31462286716632
1990	37.298676447137616
1991	37.34651570722372
1992	37.37840854728113
1993	36.99569446659225
1994	37.04353372667836
1995	37.09137298676447
1996	37.107319406793174
1997	37.12326582682188
1998	37.13921224685058
1999	37.39435496730984
2000	37.474087067453354
2001	37.49003348748206
2002	37.569765587625575
2003	37.79301546802743
2004	36.836230266305215
2005	40.025514272045925
2006	38.90926487003667
2007	38.1119438686015
2008	41.38095997448573
2009	41.62015627491628
2010	41.779620475203316
2011	43.53372667836071
2012	43.69319087864774
2013	43.69319087864774
2014	43.69319087864774
2015	44.26994975199134
2016	44.43151891167014
2017	44.59631945454252
2018	45.44807965860597
2019	45.44729470728513
2020	45.457484642741676
2021	45.457484642741676