Year	% of land area
1992	38.721264737691854
1993	38.73681561548119
1994	38.75423122738109
1995	38.76854601305432
1996	38.77836190719811
1997	38.786440253604454
1998	38.7914864837283
1999	38.789157837108526
2000	38.79264083765608
2001	38.831474136638846
2002	38.870687693329366
2003	38.907763333684166
2004	38.94433507680202
2005	38.98142164905422
2006	38.99962352185735
2007	39.03901878353838
2008	39.07958960751479
2009	39.11853483551684
2010	39.157674117276386
2011	39.17204732327981
2012	39.18670523897862
2013	39.201041031285754
2014	39.217294593864935
2015	39.22343780606183
2016	39.24216667522888
2017	39.26165445164375
2018	39.27415587481293
2019	39.28694624813319
2020	39.3051266358553
2021	39.31768473267096