Year	% of land area
1990	0.31884057971014496
1991	0.34057971014492755
1992	0.35211267605633806
1993	0.37323943661971826
1994	0.39436619718309857
1995	0.4154929577464789
1996	0.43661971830985913
1997	0.45774647887323944
1998	0.47887323943661975
1999	0.5
2000	0.5211267605633803
2001	0.5422535211267606
2002	0.5633802816901409
2003	0.576388888888889
2004	0.589041095890411
2005	0.6013513513513513
2006	0.6216216216216216
2007	0.6333333333333333
2008	0.6447368421052633
2009	0.6644736842105263
2010	0.6824146981627297
2011	0.6988265971316819
2012	0.7168831168831168
2013	0.7376623376623376
2014	0.7574578469520103
2015	0.7712082262210797
2016	0.7958921694480102
2017	0.8205128205128205
2018	0.8483290488431876
2019	0.8717948717948718
2020	0.89171974522293
2021	0.9113924050632912