Year	% of land area
1961	6.422157966823923
1962	6.5439050372850405
1963	6.848272713437834
1964	7.00045655151423
1965	7.593973520012175
1966	7.609191903819815
1967	7.76137574189621
1968	7.913559579972606
1969	8.065743418049003
1970	8.20270887231776
1971	8.370111094201796
1972	8.613605235124028
1973	8.826662608430984
1974	9.03971998173794
1975	9.283214122660173
1976	9.587581798812966
1977	9.891949474965758
1978	10.348500989194948
1979	10.65286866534774
1980	10.957236341500533
1981	11.413787855729723
1982	11.718155531882514
1983	12.022523208035308
1984	12.174707046111703
1985	12.78344239841729
1986	13.863947648759703
1987	14.914016131486838
1988	15.827119159945212
1989	16.861969258864708
1990	16.89240602647999
1991	16.983716329325826
1992	17.044589864556382
1993	17.333739156901537
1994	17.598539035154467
1995	17.60462638867752
1996	17.60462638867752
1997	17.607670065439052
1998	17.607670065439052
1999	17.607670065439052
2000	17.607670065439052
2001	17.607670065439052
2002	17.607670065439052
2003	17.912037741591842
2004	17.957692893014762
2005	17.957692893014762
2006	17.957692893014762
2007	18.246842185359917
2008	18.246842185359917
2009	18.535991477705068
2010	19.022979759549536
2011	19.418657738548166
2012	20.318977324608127
2013	21.21929691066809
2014	21.30573733069548
2015	22.704793790899405
2016	22.705828640998327
2017	22.705828640998327
2018	22.705828640998327
2019	22.705828640998327
2020	22.705828640998327
2021	22.705828640998327