Year	sq. km
1961	25680
1962	25050
1963	24900
1964	25060
1965	26720
1966	27800
1967	28010
1968	28010
1969	28350
1970	28430
1971	28520
1972	28550
1973	28550
1974	28430
1975	28250
1976	27300
1977	26350
1978	25400
1979	24470
1980	24450
1981	24680
1982	24452.4
1983	24347.4
1984	24582.6
1985	24970
1986	25670
1987	25470
1988	25810
1989	25710
1990	26480
1991	26430
1992	29962.8
1993	30151.8
1994	30126.6
1995	32830
1996	31764.6
1997	32449.2
1998	32596.2
1999	34830
2000	32910
2001	33380
2002	34240
2003	34090
2004	34780
2005	35230
2006	35330
2007	35380
2008	35420
2009	36890
2010	36710
2011	36200
2012	36960
2013	37309.7
2014	37151.9
2015	37898.771
2016	37337.654
2017	38369.687999999995
2018	38630
2019	39220
2020	39710
2021	40310