Year	sq. km
1961	19606541
1962	19606541
1963	19606541
1964	19606541
1965	19606541
1966	19606541
1967	19606541
1968	19606541
1969	19606541
1970	19606541
1971	19606541
1972	19606541
1973	19606541
1974	19606141
1975	19605741
1976	19605741
1977	19605741
1978	19605741
1979	19605741
1980	19605741
1981	19605741
1982	19605741
1983	19605741
1984	19605741
1985	19605741
1986	19605741
1987	19605741
1988	19605741
1989	19605741
1990	19605741
1991	19606621
1992	20185971
1993	20185971
1994	20185971
1995	20185971
1996	20185971
1997	20185971
1998	20185971
1999	20185971
2000	20185971
2001	20185971
2002	20185961
2003	20185771
2004	20334210.922
2005	20334236.092
2006	20334378.252
2007	20334454.665
2008	20334196.89
2009	20331169.284
2010	20331097.055
2011	20331155.05
2012	20454945.142
2013	20454640.325999998
2014	20454563.467
2015	20454617.128
2016	20454324.968
2017	20454293.053
2018	20454358.143
2019	20454370.404
2020	20454301.094
2021	20454306.094