Year Percent 1990 20.645 1991 20.847 1992 21.035 1993 21.209 1994 21.393 1995 21.601 1996 21.75 1997 21.901 1998 22.117 1999 22.323 2000 22.516 2001 22.289 2002 22.143 2003 22.083 2004 22.132 2005 22.572 2006 23.111 2007 23.691 2008 24.149 2009 24.61 2010 24.97 2011 25.147 2012 25.242 2013 25.273 2014 25.319 2015 25.433 2016 25.686 2017 25.901 2018 26.103 2019 26.294 2020 26.473 2021 26.652 2022 26.821 2023 26.971 2024 27.086 2025 27.153 2026 27.169 2027 27.134 2028 27.061 2029 26.968 2030 26.87