Year Percent 2000 27.56866 2001 27.88939 2002 28.23157 2003 28.57424 2004 28.9174 2005 29.26105 2006 29.60518 2007 29.9498 2008 30.29491 2009 30.64051 2010 30.9866 2011 31.33317 2012 31.68023 2013 32.02778 2014 32.37582 2015 32.72435 2016 33.07336 2017 33.42286 2018 33.77285 2019 34.12333 2020 34.47429 2021 34.82574 2022 35.17768