Year	% of land area
1992	0.7928852821592355
1993	0.7884393817110352
1994	0.7925335268726295
1995	0.7563988516839871
1996	0.7515750426030697
1997	0.7543136517732146
1998	0.7525839556112155
1999	0.7542296302899666
2000	0.751828639261119
2001	0.7492670119117417
2002	0.7368185775048239
2003	0.735362096892826
2004	0.7288011803738235
2005	0.734094980162491
2006	0.738398002125537
2007	0.7343237320920615
2008	0.7338182003476179
2009	0.7312993515138475
2010	0.7325647585504033
2011	0.7275195984149703
2012	0.7448102653367097
2013	0.7382513468504672
2014	0.7367035092515639
2015	0.7421125348617795
2016	0.7373037455559504
2017	0.7429417731195632
2018	0.751035486226323
2019	0.7564915436375784
2020	0.7537334853679791
2021	0.7558936505388746