Year	% of land area
1992	33.21409407977106
1993	33.27669468789126
1994	33.33929529601144
1995	33.40189590413164
1996	33.4226509467667
1997	33.48517327617006
1998	33.58969772849222
1999	33.65229833661241
2000	33.713692946058096
2001	33.77629131492345
2002	33.83888968378881
2003	33.869987849331714
2004	33.93252805374884
2005	33.99506825816596
2006	34.05760846258309
2007	34.120148667000215
2008	34.18268887141734
2009	34.245229075834466
2010	34.30776928025159
2011	34.314916732184976
2012	34.32206418411836
2013	34.329211636051745
2014	34.33635908798514
2015	34.343506539918515
2016	34.381391608891434
2017	34.51519548281038
2018	34.55989564720177
2019	34.60456722178543
2020	34.65171551107934
2021	34.69639027877055