Year	sq. km
1961	26120
1962	26170
1963	26240
1964	26290
1965	26340
1966	26390
1967	26440
1968	26540
1969	26590
1970	26640
1971	26690
1972	26740
1973	26790
1974	26840
1975	26890
1976	26940
1977	26990
1978	27090
1979	27190
1980	27240
1981	27290
1982	27440
1983	27490
1984	27640
1985	28140
1986	28190
1987	28240
1988	28250
1989	28250
1990	28250
1991	28250
1992	28150
1993	28110
1994	28100
1995	28100
1996	28100
1997	28090
1998	28090
1999	28040
2000	28100
2001	30015.2
2002	32300.8
2003	35666.7
2004	37727.3
2005	38120.2
2006	40298.8
2007	36237.2
2008	37122.3
2009	38009.7
2010	39303.8
2011	40176.3
2012	38366.5
2013	39486.5
2014	39490
2015	39490
2016	39490
2017	39490
2018	39490
2019	39490
2020	39490
2021	39490