Year	% of land area
2000	22.03764861294584
2001	22.112186261558783
2002	22.186723910171732
2003	22.261261558784675
2004	22.33579920739762
2005	22.410336856010566
2006	22.484874504623516
2007	22.559412153236458
2008	22.633949801849408
2009	22.708487450462354
2010	22.783025099075296
2011	22.779260237780715
2012	22.77549537648613
2013	22.771730515191546
2014	22.76796565389696
2015	22.764200792602377
2016	22.764200792602377
2017	22.764200792602377
2018	22.764200792602377
2019	22.764200792602377
2020	22.764200792602377
2021	22.764200792602377