Year	sq. km
1961	16114384.700000001
1962	16175216.8
1963	16241025
1964	16299045.5
1965	16364107.700000001
1966	16434023.600000001
1967	16498318.100000001
1968	16576633.3
1969	16657758.700000001
1970	16745658.4
1971	16846345.1
1972	16959495.6
1973	17068175.427
1974	17178851.455000002
1975	17267130.382
1976	17387249.742
1977	17514895.503
1978	17643762.664
1979	17756760.991
1980	17863671.198
1981	17948389.245
1982	18062740.473
1983	18215208.200000003
1984	18363237.227
1985	18545436.825
1986	18628693.482
1987	18726346.309
1988	18790989.936
1989	18862918.564
1990	18957457.891000003
1991	18988698.018
1992	19007223.085
1993	19023699.333
1994	19047416.876
1995	18980740.927
1996	18972373.424999997
1997	19000599.772000004
1998	19005265.235
1999	19027243.078
2000	19045736.231
2001	19029806.523000002
2002	19040739.6
2003	19052058.372
2004	19066332.016
2005	19074521.631
2006	19072345.621999998
2007	19085409.630000003
2008	19026770.34
2009	19005921.61
2010	19084719
2011	19062587.484
2012	19066840.267
2013	19065484.805
2014	19025154.915
2015	19028681.718000002
2016	19016818.442
2017	19010295.195
2018	18996888.041
2019	18980143.84
2020	19017642.13
2021	19023454.529