Year	% of land area
1990	39.46174863387978
1991	39.574316939890714
1992	39.686885245901635
1993	39.79945355191257
1994	39.9120218579235
1995	40.024590163934434
1996	40.137158469945355
1997	40.24972677595628
1998	40.36229508196721
1999	40.47486338797815
2000	42.79746470757706
2001	42.82368193604149
2002	42.849899164505906
2003	42.876116392970324
2004	42.90233362143475
2005	42.92855084989916
2006	42.954768078363585
2007	42.980985306828
2008	43.00720253529242
2009	43.03341976375684
2010	43.059636992221265
2011	43.059636992221265
2012	43.059636992221265
2013	43.059636992221265
2014	43.059636992221265
2015	43.059636992221265
2016	43.059636992221265
2017	43.059636992221265
2018	43.059636992221265
2019	43.059636992221265
2020	43.059636992221265
2021	43.059636992221265