Year	% of land area
2000	28.46763540290621
2001	27.906208718626157
2002	27.476882430647294
2003	27.575957727873185
2004	27.741083223249667
2005	27.840158520475562
2006	27.807133421400266
2007	27.70805812417437
2008	27.873183619550858
2009	27.741083223249667
2010	27.542932628797885
2011	27.245706737120212
2012	26.51915455746367
2013	26.948480845442536
2014	26.981505944517835
2015	27.39431968295905
2016	28.051519154557464
2017	27.60898282694848
2018	28.07133421400264
2019	28.311955085865257
2020	28.562635402906206
2021	28.58784676354029