Year	sq. km
1961	5671608.4
1962	5704550.5
1963	5739509.7
1964	5775211.2
1965	5816715.4
1966	5856703.3
1967	5898288.8
1968	5937755
1969	5984831.4
1970	6036787.1
1971	6075409.8
1972	6133412.3
1973	6195990.9
1974	6274906.7
1975	6329273.4
1976	6247021.533000001
1977	6321076.067
1978	6387812
1979	6428443.1
1980	6479102
1981	6537549.9
1982	6640149.9
1983	6751222.4
1984	6857523.2
1985	7011769.5
1986	7097415
1987	7188693
1988	7263770
1989	7337971
1990	7410238
1991	7438952
1992	7442144
1993	7443835
1994	7485352
1995	7496055
1996	7504998
1997	7620358.5
1998	7629543
1999	7666319.5
2000	7689362
2001	7717253.444
2002	7738259.8889999995
2003	7602997.733000001
2004	7624207.778
2005	7636167.322
2006	7668127.666999999
2007	7691891.1110000005
2008	7708416.556
2009	7724797.562
2010	7726213.3
2011	7733581.938
2012	7731250.255
2013	7733092.6959999995
2014	7727265.761
2015	7744349.279000001
2016	7755931.799999999
2017	7787571.2190000005
2018	7785703.5030000005
2019	7783023.458
2020	7781277.443000001
2021	7786882.4969999995