Year Percent 2000 39.20514 2001 39.02032 2002 38.8355 2003 38.65067 2004 38.46585 2005 37.59396 2006 36.72869 2007 35.87007 2008 35.01807 2009 34.17271 2010 33.33399 2011 32.5019 2012 31.67644 2013 30.85762 2014 30.04543 2015 29.23988 2016 28.44096 2017 27.64868 2018 26.86303 2019 26.08401 2020 25.31163 2021 24.54589 2022 24.54589