Year	% of land area
1990	53.30961433716386
1991	53.037975023482
1992	52.76633570980014
1993	52.49469639611828
1994	52.22305708243642
1995	51.95141776875456
1996	51.67977845507269
1997	51.40813914139084
1998	51.20916483669567
1999	50.93713952332208
2000	50.665114209948484
2001	50.389138284736234
2002	50.11568787141609
2003	49.83967316946699
2004	49.563658742964876
2005	49.28759540571616
2006	49.01163071629992
2007	48.735617116136254
2008	48.4596279713463
2009	48.18363882655635
2010	47.90764968176639
2011	47.761159189935356
2012	47.61736651985988
2013	47.478818097802545
2014	47.335490045980016
2015	47.1909784911788
2016	47.04286407214674
2017	46.87071558746679
2018	46.75486776273044
2019	46.63174952681631
2020	46.51281370019195
2021	46.389877843824394