Year	% of land area
1990	6.468957555002077
1991	6.40727091116646
1992	6.3455842673308425
1993	6.283897623495226
1994	6.22221097965961
1995	6.160524335823993
1996	6.098837691988377
1997	6.037151048152761
1998	5.975464404317145
1999	5.913777760481527
2000	5.852091116645911
2001	5.797928341635533
2002	5.7437655666251555
2003	5.689602791614778
2004	5.6354400166044005
2005	5.581277241594022
2006	5.527114466583645
2007	5.472951691573267
2008	5.41878891656289
2009	5.364626141552511
2010	5.310463366542134
2011	5.268659194686593
2012	5.2268550228310495
2013	5.185050850975508
2014	5.143246679119967
2015	5.101442507264426
2016	5.017953507679535
2017	4.994188459941884
2018	4.940561436280615
2019	4.886934412619344
2020	4.833307388958074
2021	4.779680365296803