Year % 2000 28.758019138054863 2001 28.771731327928027 2002 28.44589851011955 2003 28.133514327380695 2004 27.896894372976448 2005 27.2202345308825 2006 26.4838184987188 2007 26.06620425268151 2008 25.14466483541623 2009 24.565286897770402 2010 23.79512736309234 2011 23.32862200128331 2012 22.863133967977372 2013 22.333412161162432 2014 22.174290456361476 2015 21.77006688241788 2016 21.552676470666515 2017 21.352836266783008 2018 21.292374380700306 2019 20.985414018121617