Year	sq. km
1990	181420.9
1991	181056.9
1992	180692.9
1993	180328.9
1994	179964.9
1995	179600.9
1996	179236.9
1997	178872.9
1998	178508.9
1999	178144.9
2000	177780.9
2001	177416.9
2002	177052.9
2003	176688.9
2004	176324.9
2005	175960.9
2006	175596.9
2007	175232.9
2008	174868.9
2009	174504.9
2010	174140.9
2011	173776.9
2012	173412.9
2013	173048.9
2014	172684.9
2015	172320.9
2016	171956.9
2017	171592.9
2018	171228.9
2019	170864.9
2020	170500.9
2021	170136.9