Year	sq. km
1961	5303384.3
1962	5312524.3
1963	5319354.3
1964	5326414.3
1965	5328724.3
1966	5326074.3
1967	5329674.3
1968	5340234.3
1969	5349304.3
1970	5342394.3
1971	5347394.3
1972	5360934.3
1973	5366146.3
1974	5361057.3
1975	5364507.3
1976	5372184.3
1977	5374764.3
1978	5379044.3
1979	5381594.3
1980	5390434.3
1981	5388764.3
1982	5391784.3
1983	5400054.3
1984	5399334.3
1985	5421784.3
1986	5459644.3
1987	5476174.3
1988	5511144.3
1989	5529804.3
1990	5548434.3
1991	5563554.7
1992	5585063.702
1993	5445234.384
1994	5479275.182
1995	5509104.072000001
1996	5535175.618000001
1997	5564962.609999999
1998	5584239.716
1999	5610974.15
2000	5640712.362
2001	5674009.640000001
2002	5691348.342999999
2003	5748887.309
2004	5763220.78
2005	5834252.579
2006	5861187.364
2007	5886787.379000001
2008	5894895.698
2009	5928427.001
2010	5962970.4459999995
2011	5992629.910999999
2012	6047513.327
2013	6076192.323
2014	6094951.887999999
2015	6108227.732
2016	6130059.111999999
2017	6150190.843
2018	6166220.737999999
2019	6174828.5600000005
2020	6185615.98
2021	6191413.58