Year Percent 2000 17.1198 2001 18.42287 2002 19.72593 2003 21.029 2004 22.41962 2005 23.82046 2006 25.23152 2007 26.65279 2008 28.08428 2009 29.52599 2010 30.97792 2011 32.44006 2012 33.91242 2013 35.395 2014 36.88779 2015 38.3908 2016 39.90403 2017 41.42748 2018 42.96114 2019 44.50502 2020 46.05912 2021 47.62344 2022 49.01846