Year Percent 1999-01-01 49.44990000000000000 2000-01-01 37.93650000000000000 2001-01-01 56.47710000000000000 2002-01-01 61.87070000000000000 2003-01-01 43.82080000000000000 2004-01-01 41.50580000000000000 2005-01-01 41.42070000000000000 2006-01-01 40.20830000000000000 2007-01-01 29.91440000000000000 2008-01-01 25.97030000000000000 2009-01-01 2.10420000000000000 2010-01-01 0.37472900000000000 2011-01-01 0.53821800000000000 2012-01-01 0.45946099999999995 2013-01-01 0.31929300000000000 2014-01-01 0.36922699999999997 2015-01-01 0.46732500000000000 2016-01-01 0.40135600000000000