Year	sq. km
1961	5640
1962	5640
1963	5640
1964	5640
1965	5640
1966	5640
1967	5640
1968	5640
1969	5640
1970	5640
1971	5640
1972	5640
1973	5640
1974	5640
1975	5640
1976	5640
1977	5640
1978	5640
1979	5640
1980	5640
1981	5640
1982	5640
1983	5640
1984	5640
1985	5640
1986	5640
1987	5640
1988	5640
1989	5640
1990	5640
1991	5640
1992	5640
1993	5600
1994	5490
1995	5380
1996	5250
1997	4950
1998	4900
1999	5000
2000	5180
2001	5100
2002	5050
2003	5100
2004	4920
2005	5090
2006	4910
2007	4980
2008	6185.6
2009	6251.2
2010	6238.6
2011	6206.1
2012	6117.9
2013	6102.1
2014	6148.4
2015	6164.9
2016	6174.8
2017	6150.4
2018	6120
2019	6122.8
2020	6104.9
2021	6109.6