Year Percent 1992 0.025 1993 0.021 1994 0.016 1995 0.015 1996 0.015 1997 0.016 1998 0.016 1999 0.016 2000 0.016 2001 0.017 2002 0.016 2003 0.017 2004 0.017 2005 0.016 2006 0.016 2007 0.016 2008 0.017 2009 0.018 2010 0.017 2011 0.017 2012 0.016 2013 0.018 2014 0.018 2015 0.018 2016 0.018 2017 0.018 2018 0.018 2019 0.018 2020 0.018 2021 0.018 2022 0.018 2023 0.018 2024 0.018