Year	sq. km
1961	12931009.4
1962	13013068.5
1963	13096639.7
1964	13175798.2
1965	13269373.4
1966	13351750.3
1967	13431314.8
1968	13515044
1969	13603781.4
1970	13696285.1
1971	13804569.8
1972	13899656.3
1973	14007182.9
1974	14122063.7
1975	14213151.4
1976	14186152.95
1977	14310229.9
1978	14425875.25
1979	14510686.766999999
1980	14614881.163
1981	14691880.4
1982	14811804.817
1983	14942646.733000001
1984	15078292.2
1985	15219145.237
1986	15268741.333
1987	15317644.6
1988	15364890.667
1989	15415158.733000001
1990	15462378.8
1991	15508454.046999998
1992	15501733.933
1993	15453808
1994	15471254.067
1995	15385653.133000001
1996	15377986.2
1997	15507550.167
1998	15509609.133
1999	15516134.100000001
2000	15523594.267
2001	15480197.777
2002	15471948.888999999
2003	15319259.4
2004	15307784.111000001
2005	15310498.322
2006	15314137.667
2007	15312661.411000002
2008	15329176.696
2009	15334180.652
2010	15392297.92
2011	15383909.360000001
2012	15385105.473
2013	15405823.704
2014	15388289.290000001
2015	15396246.72
2016	15393026.670000002
2017	15375904.402
2018	15368189.576
2019	15343718.072
2020	15340658.729
2021	15324865.093999999