Year	% of land area
1961	29.35199819372319
1962	29.35199819372319
1963	30.480921201174084
1964	30.480921201174084
1965	30.480921201174084
1966	30.480921201174084
1967	30.480921201174084
1968	30.480921201174084
1969	30.480921201174084
1970	31.60984420862497
1971	32.738767216075864
1972	32.738767216075864
1973	32.738767216075864
1974	32.738767216075864
1975	32.738767216075864
1976	32.738767216075864
1977	32.738767216075864
1978	33.86769022352675
1979	33.86769022352675
1980	33.86769022352675
1981	34.996613230977644
1982	34.996613230977644
1983	34.996613230977644
1984	34.996613230977644
1985	36.12553623842854
1986	36.12553623842854
1987	36.12553623842854
1988	36.12553623842854
1989	36.12553623842854
1990	35.21109731316324
1991	35.63105667193497
1992	36.051016030706705
1993	36.47097538947844
1994	36.89093474825017
1995	37.3108941070219
1996	37.730853465793636
1997	38.04809212011741
1998	38.15759765184015
1999	38.27048995258524
2000	38.383382253330325
2001	38.49627455407541
2002	38.6091668548205
2003	38.688191465342065
2004	39.238089862271394
2005	39.86701286972229
2006	40.49593587717318
2007	41.11356965454956
2008	41.74125084669226
2009	41.980921201174084
2010	42.22059155565591
2011	42.46026191013773
2012	42.33189659065252
2013	42.93960261910137
2014	43.1792729735832
2015	43.418943328065026
2016	43.65861368254685
2017	43.898284037028674
2018	44.1379543915105
2019	44.37762474599232
2020	44.616391962068185
2021	44.616391962068185