Year	% of land area
1992	0.3834221592650788
1993	0.3829569425417459
1994	0.3896897785452799
1995	0.35441874719692396
1996	0.35112303144787804
1997	0.3511975572861064
1998	0.34434765770236614
1999	0.34204008550665743
2000	0.34001195051103594
2001	0.3361741534507486
2002	0.334759158548439
2003	0.3358670094735343
2004	0.33193012733802885
2005	0.33346710528558277
2006	0.3476700897220769
2007	0.34797125133362783
2008	0.3483379959706882
2009	0.34818311141319214
2010	0.35068924062956064
2011	0.3541200750048442
2012	0.36034994833355566
2013	0.36045280121696827
2014	0.35730916660968837
2015	0.3606118327778046
2016	0.36391134302945
2017	0.3687731393235644
2018	0.3727753369845952
2019	0.37591259131885124
2020	0.378633688716545
2021	0.3800083757483235