Year	% of land area
1991	90.86857142857143
1992	90.90857142857143
1993	90.94857142857143
1994	90.98857142857142
1995	91.02857142857144
1996	91.06857142857143
1997	91.10857142857142
1998	91.14857142857143
1999	91.18857142857144
2000	91.22857142857144
2001	91.26714285714286
2002	91.30571428571427
2003	91.34428571428572
2004	91.38285714285713
2005	91.42142857142858
2006	91.46000000000001
2007	91.49857142857142
2008	91.53714285714287
2009	91.57571428571428
2010	91.6142857142857
2011	91.65428571428572
2012	91.69428571428571
2013	91.73428571428572
2014	91.77428571428571
2015	91.81428571428573
2016	91.85714285714286
2017	91.89999999999999
2018	91.94285714285715
2019	91.98571428571428
2020	92.02857142857144
2021	92.07142857142857