Year	% of land area
1990	54.3921240336993
1991	54.09898764125531
1992	53.80585124881134
1993	53.51271485636736
1994	53.21957846392338
1995	52.92644207147941
1996	52.63330567903542
1997	52.34016928659145
1998	52.12964258187267
1999	51.83604091975829
2000	51.54243925764389
2001	51.236852248262736
2002	50.93413222311396
2003	50.62849979462067
2004	50.32286770680878
2005	50.01718020671647
2006	49.71160455322688
2007	49.405973487455725
2008	49.10037012782535
2009	48.79476676819498
2010	48.48916340856461
2011	48.325468390708664
2012	48.16349092963311
2013	48.007436136548975
2014	47.8453936810585
2015	47.68260339540839
2016	47.51773267075622
2017	47.32498058786576
2018	47.193886668810876
2019	47.05316970576616
2020	46.915725827108496
2021	46.774733635278295