Year	% of land area
1990	40.974308300395265
1991	40.40780632411067
1992	39.84130434782609
1993	39.2748023715415
1994	38.70830039525692
1995	38.14179841897233
1996	37.575296442687744
1997	37.00879446640316
1998	36.442292490118575
1999	35.87579051383399
2000	35.30928853754941
2001	34.74278656126482
2002	34.17628458498024
2003	33.60978260869565
2004	33.04328063241107
2005	32.476778656126484
2006	31.9102766798419
2007	31.343774703557308
2008	30.777272727272724
2009	30.210770750988143
2010	29.64426877470356
2011	29.077865612648218
2012	28.51146245059289
2013	27.94505928853755
2014	27.37865612648221
2015	26.81225296442688
2016	26.245059288537547
2017	25.67885375494071
2018	25.112648221343875
2019	24.545454545454547
2020	23.979249011857707
2021	23.412381422924902