Year	sq. km
1990	144360
1991	145212
1992	146064
1993	146916
1994	147768
1995	148620
1996	149472
1997	150324
1998	151176
1999	152028
2000	152880
2001	154011
2002	155142
2003	156273
2004	157404
2005	158535
2006	159666
2007	160797
2008	161928
2009	163059
2010	164190
2011	165024
2012	165858
2013	166692
2014	167526
2015	168360
2016	169194
2017	170028
2018	170862
2019	171696
2020	172530
2021	173364