Year	% of land area
1990	77.30935875216637
1991	77.12824956672443
1992	76.9471403812825
1993	76.76603119584055
1994	76.58492201039861
1995	76.40381282495667
1996	76.22270363951473
1997	76.0415944540728
1998	75.86048526863085
1999	75.67937608318891
2000	75.49826689774697
2001	75.28834488734836
2002	75.07842287694973
2003	74.86850086655113
2004	74.65857885615252
2005	74.4486568457539
2006	74.23873483535529
2007	74.02881282495667
2008	73.81889081455806
2009	73.60896880415945
2010	73.39904679376083
2011	73.24956672443675
2012	73.10008665511265
2013	72.95060658578856
2014	72.80112651646448
2015	72.65164644714038
2016	72.5021663778163
2017	72.3526863084922
2018	72.20320623916811
2019	72.05372616984403
2020	71.90424610051993
2021	71.75476603119584