Year	% of land area
1990	60.009303179606455
1991	59.34364078709796
1992	58.677978394589466
1993	58.01231600208098
1994	57.346653609572485
1995	56.68099121706399
1996	56.015328824555496
1997	55.34966643204701
1998	54.684004039538515
1999	54.01834164703002
2000	53.352679254521526
2001	52.828287480490864
2002	52.3038957064602
2003	51.779503932429535
2004	51.26452511401548
2005	50.74469664503489
2006	50.21170673481568
2007	49.68345727751255
2008	49.174851142642844
2009	48.65101943976733
2010	48.129381869393505
2011	47.68370555189885
2012	47.25036515348695
2013	46.81182091014884
2014	46.36821216390029
2015	45.924603417651745
2016	45.50189956800147
2017	45.06016085790885
2018	44.61974873601961
2019	44.175884786272405
2020	43.73403098043422
2021	43.29014662846461