Year	% of land area
1990	26.081537448064882
1991	25.96038780524476
1992	25.248809769699083
1993	25.17348297134648
1994	25.060959940806388
1995	24.943177923944535
1996	24.82539591311792
1997	24.70761389625607
1998	24.610982995285745
1999	24.493099667383767
2000	24.31876136548744
2001	24.253750355560484
2002	24.188699775575042
2003	24.123804753127036
2004	23.96720867821732
2005	23.902442175325177
2006	23.837506611973016
2007	23.772545091480463
2008	23.70794132808325
2009	23.642763062285802
2010	23.57804479769963
2011	23.486442349564253
2012	23.394906478202486
2013	23.303336220768823
2014	23.212696234282326
2015	23.117710415212283
2016	23.071766879869692
2017	22.982278760244235
2018	22.91459540890948
2019	22.848995247813246
2020	22.783987233402424
2021	22.707979244532243