Year	sq. km
1961	1729600
1962	1733780
1963	1737150
1964	1745170
1965	1756690
1966	1760650
1967	1760490
1968	1760540
1969	1749950
1970	1754860
1971	1754190
1972	1757440
1973	1769230
1974	1766569
1975	1775920
1976	1776150
1977	1778820
1978	1785690
1979	1791112
1980	1804895
1981	1798128
1982	1820910
1983	1802382
1984	1816985
1985	1826428
1986	1815012
1987	1827986.6
1988	1820293
1989	1831629.4
1990	1829014.8
1991	1839740.2
1992	1856257.6
1993	1862506
1994	1878302.4
1995	1903655.8
1996	1902968.2
1997	1912952.6
1998	1918926
1999	1927883.4
2000	1928880
2001	1936685
2002	1936555
2003	1938126
2004	1935121
2005	1935197
2006	1939157
2007	1937323.3
2008	1933501.4
2009	1934131.4
2010	1936740.4
2011	1949369.4
2012	1948477.4
2013	1950735.4
2014	1957083.4
2015	1958371.4
2016	1965976.4
2017	1970309.4
2018	1971348.4
2019	1967004.4
2020	1973974.4
2021	1971985.4