Year % of land area 1992 46.02744097000638 1993 45.118059987236755 1994 41.320995532865346 1995 45.724313975749844 1996 45.724313975749844 1997 45.91576260370134 1998 46.10721123165284 1999 47.11231652839821 2000 45.91576260370134 2001 26.021059349074665 2002 26.148691767708996 2003 24.32992980216975 2004 25.78813018506701 2005 30.41640076579451 2006 29.974473516273132 2007 29.285258455647735 2008 29.700837654567213 2009 32.76745113681691 2010 33.94335859593139 2011 34.87411047643361 2012 36.067587835466064 2013 36.545672118069405 2014 37.51316839584996 2015 34.667198723064644 2016 34.20708151080745 2017 33.58343576890535 2018 33.769758901484906 2019 35.32258064516129 2020 35.9214308527627 2021 36.3999361124421