Year	% of land area
1991	83.24565217391304
1992	83.55652173913045
1993	83.86739130434783
1994	84.17826086956522
1995	84.4891304347826
1996	84.8
1997	85.11086956521739
1998	85.42173913043479
1999	85.73260869565217
2000	86.04347826086956
2001	86.25652173913043
2002	86.46956521739129
2003	86.68260869565218
2004	86.89565217391305
2005	87.1086956521739
2006	87.32173913043478
2007	87.53478260869566
2008	87.74782608695652
2009	87.9608695652174
2010	88.17391304347827
2011	88.36086956521739
2012	88.54782608695652
2013	88.73478260869565
2014	88.92173913043479
2015	89.1086956521739
2016	89.30434782608697
2017	89.47826086956522
2018	89.67391304347827
2019	89.84782608695653
2020	90.02173913043478
2021	90.19565217391305