Year years 2003 2 2004 2 2005 2 2006 2 2007 2 2008 2 2009 2 2010 2 2011 2 2012 2.5 2013 3.5 2014 3.5 2015 3.5 2016 3.5 2017 3.5 2018 3.5 2019 3.5