Year Percent 2000 0 2001 1.01958 2002 4.04283 2003 7.09803 2004 10.18518 2005 13.30428 2006 16.45534 2007 19.63835 2008 22.8533 2009 26.10021 2010 29.37908 2011 32.68989 2012 36.03266 2013 39.40737 2014 42.81404 2015 46.25266 2016 49.72324 2017 53.22576 2018 56.76024 2019 60.32667 2020 63.92505 2021 67.55538 2022 71.21767