Year % of land area 1961 45.87722548656327 1962 45.87722548656327 1963 45.87722548656327 1964 45.87722548656327 1965 45.87898999523583 1966 45.87898999523583 1967 45.87898999523583 1968 45.87898999523583 1969 45.87898999523583 1970 45.87898999523583 1971 45.87898999523583 1972 45.88075450390839 1973 45.88075450390839 1974 45.88075450390839 1975 45.88075450390839 1976 45.88075450390839 1977 45.88075450390839 1978 45.88075450390839 1979 45.88428352125351 1980 45.88428352125351 1981 45.88428352125351 1982 45.887812538598624 1983 45.887812538598624 1984 45.887812538598624 1985 45.89134155594375 1986 45.89134155594375 1987 45.89487057328886 1988 45.89487057328886 1989 45.90369311665167 1990 45.91428016868703 1991 45.70253912797981 1992 45.61431369435181 1993 45.79076456160782 1994 45.87016745187303 1995 45.78194201824502 1996 45.78194201824502 1997 45.70253912797981 1998 45.579023520900606 1999 45.596668607626206 2000 45.79076456160782 2001 45.5260882607238 2002 45.60549115098901 2003 45.517265717361 2004 45.57196548621037 2005 45.55079138213964 2006 45.529617278068926 2007 45.49609161329028 2008 45.66724895452861 2009 45.73253577541333 2010 45.63195878107741 2011 45.74665184479382 2012 45.67783600656397 2013 45.66901346320117 2014 45.88428352125351 2015 45.63301748628095 2016 45.63301748628095 2017 45.63301748628095 2018 45.63301748628095 2019 45.633723289749966 2020 45.633723289749966 2021 45.633723289749966