Year	% of land area
1992	20.482593700806326
1993	20.6183832630352
1994	20.712114111299375
1995	20.74455940492928
1996	21.44754076691061
1997	21.64461588377375
1998	21.779473354835606
1999	22.065171392297927
2000	22.100357121239632
2001	22.222894775071424
2002	22.238495243167346
2003	22.243865847166433
2004	22.265095800270952
2005	22.298572465521413
2006	22.281786608904003
2007	22.437642958283412
2008	22.513222070267588
2009	22.681610224879574
2010	22.79447348044909
2011	22.813278811488303
2012	22.94756708364587
2013	23.292079507373668
2014	23.305469194198132
2015	23.440959074797675
2016	24.180476593685736
2017	25.33812392635068
2018	25.381711713891647
2019	25.358724320662034
2020	25.219611354451516
2021	25.275257108287963