Year	% of land area
1961	34.89664256657593
1962	35.020109354954315
1963	35.14109308595539
1964	35.262093937650306
1965	35.39310510592151
1966	35.509742825347274
1967	35.62211930151114
1968	35.76161147690156
1969	35.871400222828214
1970	36.019827869284086
1971	36.19982022909011
1972	36.41140764624024
1973	36.598423312605995
1974	36.76243245730076
1975	36.91290627530031
1976	36.891685136080895
1977	37.097060995668805
1978	37.315105520461216
1979	37.48417601779005
1980	37.64289304729735
1981	37.72333928988163
1982	37.94036416766059
1983	38.154269830316
1984	38.41677044597722
1985	38.74062080099332
1986	38.90659189199445
1987	39.114331369229
1988	39.27291953229546
1989	39.438038711448264
1990	39.586207595445366
1991	39.70527400142392
1992	36.949021322856446
1993	36.801028579721894
1994	36.90079173922323
1995	36.907656545198165
1996	36.94684008948283
1997	37.14575248887646
1998	37.20300335229171
1999	37.281502490343705
2000	37.31055693233611
2001	37.34836025161155
2002	37.390235492612824
2003	37.29766036357089
2004	37.28217390404847
2005	37.20201600504398
2006	37.25496670007419
2007	37.31480436799087
2008	37.26666337202571
2009	37.30542453248122
2010	37.43751039504218
2011	37.469661102587956
2012	37.49135797364203
2013	37.54839121676054
2014	37.529610491819646
2015	37.581567835484044
2016	37.60759179604238
2017	37.637627377412905
2018	37.65653336901047
2019	37.644562616432104
2020	37.70717177558627
2021	37.71799627038397