Year Percent 2000 17.99972 2001 19.15246 2002 20.41868 2003 21.69422 2004 22.97917 2005 24.27262 2006 25.84268 2007 27.44807 2008 29.09013 2009 30.7676 2010 32.48285 2011 34.23641 2012 36.02882 2013 37.85968 2014 39.72632 2015 41.62832 2016 43.56515 2017 45.53805 2018 47.54589 2019 49.58939 2020 51.66774 2021 53.78156 2022 55.92989