Year	% of land area
1992	40.65759236344352
1993	40.400469249682615
1994	40.818294309544086
1995	29.440596525623924
1996	30.11554469924631
1997	28.47638484902052
1998	28.106770372989214
1999	25.98550468446173
2000	25.519469040770083
2001	25.406977678499686
2002	25.631960403040484
2003	25.423047873109745
2004	26.38725954971315
2005	27.865717453838368
2006	29.81021100165523
2007	29.553087887894325
2008	29.32810516335353
2009	29.456666720233983
2010	29.006701271152398
2011	29.18347341186302
2012	29.585228277114435
2013	30.163755283076476
2014	30.083404310026197
2015	30.284281742651903
2016	31.031545792019543
2017	31.063686181239653
2018	31.14403715428994
2019	31.497581435711187
2020	31.64068777117146
2021	31.656757191065406