Year	sq. km
1961	260000
1962	260000
1963	260000
1964	260000
1965	260010
1966	260010
1967	260010
1968	260010
1969	260010
1970	260010
1971	260010
1972	260020
1973	260020
1974	260020
1975	260020
1976	260020
1977	260020
1978	260020
1979	260040
1980	260040
1981	260040
1982	260060
1983	260060
1984	260060
1985	260080
1986	260080
1987	260100
1988	260100
1989	260150
1990	260210
1991	259010
1992	258510
1993	259510
1994	259960
1995	259460
1996	259460
1997	259010
1998	258310
1999	258410
2000	259510
2001	258010
2002	258460
2003	257960
2004	258270
2005	258150
2006	258030
2007	257840
2008	258810
2009	259180
2010	258610
2011	259260
2012	258870
2013	258820
2014	260040
2015	258616
2016	258616
2017	258616
2018	258616
2019	258620
2020	258620
2021	258620