Year Number 2004-01-01 0.1825 2005-01-01 0.2457 2006-01-01 0.2162 2007-01-01 0.2058 2008-01-01 0.2199 2009-01-01 0.2365 2010-01-01 0.2583 2011-01-01 0.2731 2012-01-01 0.3117 2013-01-01 0.6289 2014-01-01 1.1747 2015-01-01 2.7019 2016-01-01 3.4993