Year	% of land area
1990	45.75460494425593
1991	45.83030780416868
1992	45.90601066408143
1993	45.98171352399418
1994	46.05741638390693
1995	46.13311924381968
1996	46.20882210373242
1997	46.284524963645175
1998	46.36022782355793
1999	46.43593068347067
2000	46.511633543383425
2001	46.542001938923896
2002	46.57237033446437
2003	46.60273873000485
2004	46.63310712554532
2005	46.66347552108579
2006	46.69384391662628
2007	46.72421231216675
2008	46.75458070770722
2009	46.784949103247705
2010	46.815317498788175
2011	46.858919049927295
2012	46.902520601066406
2013	46.946122152205525
2014	46.989723703344644
2015	47.03332525448376
2016	47.07695104217159
2017	47.120455647115854
2018	47.16396025206011
2019	47.20746485700436
2020	47.250969461948614
2021	47.294474066892874