Year	% of land area
1992	6.144612746498999
1993	6.208916833380966
1994	6.073163761074593
1995	6.0302943698199485
1996	5.794512717919406
1997	5.794512717919406
1998	5.6016004572735065
1999	5.6016004572735065
2000	5.6016004572735065
2001	5.594455558731066
2002	5.580165761646184
2003	5.587310660188625
2004	5.558731066018863
2005	5.408688196627607
2006	5.265790225778794
2007	5.33009431266076
2008	5.294369819948557
2009	5.36867676478994
2010	5.336524721348957
2011	5.3100885967419265
2012	5.277222063446699
2013	5.4972849385538725
2014	5.765711238885767
2015	5.971611787592766
2016	6.167591325023417
2017	6.037178471071403
2018	6.047986166150299
2019	6.082570790402767
2020	6.047986166150299
2021	6.037898984076662