Year	% of land area
1961	7.7631578947368425
1962	7.799707602339182
1963	7.83625730994152
1964	7.85453216374269
1965	7.89108187134503
1966	7.931286549707603
1967	7.9678362573099415
1968	8.00438596491228
1969	8.048245614035087
1970	8.099415204678364
1971	8.04093567251462
1972	8.340643274853802
1973	8.600146198830409
1974	8.892543859649123
1975	9.1593567251462
1976	9.320175438596491
1977	9.502923976608187
1978	9.685672514619883
1979	9.868421052631579
1980	10.032894736842106
1981	10.197368421052632
1982	10.380116959064328
1983	10.544590643274853
1984	10.70906432748538
1985	10.891812865497077
1986	11.056286549707602
1987	11.239035087719298
1988	12.77046783625731
1989	12.902046783625732
1990	12.810672514619883
1991	12.719298245614036
1992	12.627923976608187
1993	12.53654970760234
1994	12.2843567251462
1995	12.353801169590643
1996	12.719298245614036
1997	13.815789473684212
1998	14.25438596491228
1999	14.605263157894738
2000	14.95248538011696
2001	15.303362573099417
2002	15.65423976608187
2003	16.001461988304094
2004	16.35233918128655
2005	16.703216374269005
2006	17.050438596491226
2007	17.401315789473685
2008	17.75219298245614
2009	18.099415204678362
2010	18.45029239766082
2011	18.797514619883042
2012	19.148391812865498
2013	19.499269005847953
2014	19.846491228070175
2015	20.19736842105263
2016	20.54824561403509
2017	20.89546783625731
2018	21.246345029239766
2019	21.59722222222222
2020	21.944444444444443
2021	22.295321637426902