Year	% of land area
1990	53.505568517517105
1991	53.22976322668331
1992	52.95395793584952
1993	52.678152645015736
1994	52.40234735418194
1995	52.126542063348154
1996	51.85073677251436
1997	51.57493148168058
1998	51.372492973657444
1999	51.096293232696084
2000	50.82009349173471
2001	50.539538442811434
2002	50.258983393888165
2003	49.97842834496489
2004	49.69787329604163
2005	49.41731824711836
2006	49.136763198195084
2007	48.856208149271815
2008	48.575653100348546
2009	48.29509805142528
2010	48.014543002502
2011	47.86674776354208
2012	47.71895252458216
2013	47.57115728562223
2014	47.42388597192686
2015	47.27608910015019
2016	47.124002657103674
2017	46.95011984887371
2018	46.83350497592785
2019	46.70958619208361
2020	46.589868582818006
2021	46.466128745117494