Year	% of land area
1990	53.35984491830518
1991	53.11029908612572
1992	52.86075325394628
1993	52.611207421766814
1994	52.36166158958737
1995	52.11211575740793
1996	51.86256992522846
1997	51.61302409304902
1998	51.36347826086956
1999	51.11393242869011
2000	50.86438659651067
2001	50.67834579525524
2002	50.49230499399982
2003	50.306264192744386
2004	50.12022339148897
2005	49.93418259023355
2006	49.748141788978124
2007	49.562100987722694
2008	49.37606018646727
2009	49.190019385211855
2010	49.003978583956425
2011	48.80850364626604
2012	48.61302870857565
2013	48.417553770885256
2014	48.22207883319487
2015	48.02660389550448
2016	47.771328348564566
2017	47.53274254592449
2018	47.312138835041075
2019	47.10953567802086
2020	46.92491461275731
2021	46.72830545555247