Year	% of land area
1961	12.788222774033345
1962	12.965590634976943
1963	13.14295849592054
1964	13.320326356864138
1965	13.497694217807732
1966	13.76374600922313
1967	14.118481731110322
1968	14.38453352252572
1969	15.138346931536006
1970	15.315714792479604
1971	15.759134444838596
1972	16.02518623625399
1973	16.202554097197588
1974	16.468605888612984
1975	16.82334161050018
1976	17.089393401915572
1977	17.35544519333097
1978	17.532813054274566
1979	17.710180915218164
1980	17.976232706633557
1981	18.242284498048953
1982	18.53494146860589
1983	18.623625399077685
1984	18.712309329549488
1985	18.88967719049308
1986	19.421780773323874
1987	19.51046470379567
1988	19.599148634267472
1989	19.687832564739267
1990	20.13125221709826
1991	20.21993614757006
1992	20.35296204327776
1993	20.574671869457255
1994	21.28414331323164
1995	22.348350478893224
1996	24.033345157857397
1997	25.629655906349768
1998	27.04859879389854
1999	27.580702376729338
2000	28.334515785739622
2001	28.955303299042214
2002	29.8421426037602
2003	30.746718694572543
2004	30.746718694572543
2005	30.897481376374603
2006	29.620432777580703
2007	29.709116708052502
2008	31.48279531748847
2009	32.369634622206455
2010	32.369634622206455
2011	32.369634622206455
2012	33.25647392692444
2013	35.03015253636041
2014	35.03015253636041
2015	35.03015253636041
2016	35.03015253636041
2017	35.03015253636041
2018	35.03015253636041
2019	35.03015253636041
2020	35.03015253636041
2021	35.03015253636041