Year	% of land area
1990	4.191919191919193
1991	4.191919191919193
1992	4.191919191919193
1993	4.191919191919193
1994	4.191919191919193
1995	4.191919191919193
1996	4.191919191919193
1997	4.191919191919193
1998	4.191919191919193
1999	4.191919191919193
2000	4.191919191919193
2001	4.287878787878788
2002	4.383838383838383
2003	4.479797979797979
2004	4.575757575757576
2005	4.671717171717172
2006	4.767676767676767
2007	4.863636363636363
2008	4.959595959595959
2009	5.055555555555555
2010	5.151515151515151
2011	5.151515151515151
2012	5.151515151515151
2013	5.151515151515151
2014	5.151515151515151
2015	5.151515151515151
2016	5.151515151515151
2017	5.151515151515151
2018	5.151515151515151
2019	5.151515151515151
2020	5.151515151515151
2021	5.151515151515151