Year	% of land area
1961	66.10586156564493
1962	66.04440347238227
1963	66.10586156564493
1964	66.37474072366905
1965	67.42721057079204
1966	67.58853806560651
1967	67.93423984020896
1968	67.82668817699931
1969	67.68072520550051
1970	67.88814627026196
1971	67.88814627026196
1972	70.16209572098026
1973	70.1467311976646
1974	70.1467311976646
1975	70.2466005992164
1976	70.20050702926942
1977	70.1467311976646
1978	70.1006376277176
1979	70.04686179611278
1980	70.06990858108627
1981	69.97772144119229
1982	69.93931013290313
1983	69.82407620803565
1984	70.56157332718752
1985	70.30805869247907
1986	70.37719904739956
1987	70.94568641007912
1988	73.26572943074441
1989	73.38864561726972
1990	72.64346623646001
1991	72.09802565875394
1992	66.13659061227625
1993	65.34531766151956
1994	64.59245601905201
1995	64.56172697242069
1996	64.20066067450257
1997	64.45417530921104
1998	64.94584005531229
1999	64.8075593454713
2000	64.14688484289775
2001	63.78581854497965
2002	63.401705462088046
2003	63.20964892064224
2004	62.55665667972651
2005	60.774371975109474
2006	60.536221863716676
2007	60.044557117615426
2008	59.944687716063605
2009	59.89091188445879
2010	59.85250057616962
2011	58.98440500883461
2012	58.92294691557195
2013	58.98440500883461
2014	58.915264653914114
2015	59.40109088115542
2016	59.646692786356304
2017	59.59383882615042
2018	59.70884228316816
2019	61.20457862794807
2020	61.45809326265652
2021	62.303142045018056