Year	% of land area
1990	70.45802056438394
1991	70.0056543680771
1992	69.55328817177028
1993	69.10092197546344
1994	68.64855577915661
1995	68.19618958284977
1996	67.74382338654293
1997	67.2914571902361
1998	66.83909099392928
1999	66.38672479762245
2000	65.93435860131561
2001	65.46167089807062
2002	64.98898319482565
2003	64.51629549158065
2004	64.04360778833569
2005	63.5709200850907
2006	63.09823238184572
2007	62.62554467860074
2008	62.15285697535576
2009	61.68016927211079
2010	61.207481568865795
2011	61.023328156743005
2012	60.839174744620216
2013	60.65502133249742
2014	60.47086792037463
2015	60.28671450825184
2016	60.07103255030426
2017	59.832881478415054
2018	59.70842795167346
2019	59.558526179269556
2020	59.41747805133678
2021	59.27052749774471