Year	% of land area
1990	62.34302062089281
1991	62.21624178563335
1992	62.0894629503739
1993	61.96268411511443
1994	61.83590527985498
1995	61.709126444595505
1996	61.582347609336054
1997	61.45556877407658
1998	61.32878993881713
1999	61.202011103557666
2000	61.07523226829821
2001	60.966593020620884
2002	60.85795377294359
2003	60.749314525266264
2004	60.64067527758894
2005	60.532036029911616
2006	60.423396782234306
2007	60.314757534556996
2008	60.20611828687967
2009	60.09747903920236
2010	59.98883979152504
2011	58.01466122818943
2012	56.04048266485384
2013	54.066304101518234
2014	52.09212553818264
2015	50.11794697484704
2016	49.235950600498526
2017	48.35395422615001
2018	47.47195785180149
2019	46.58996147745299
2020	45.70796510310446
2021	44.82596872875595