Year % 1997 3.73134328358209 1999 8 2000 8 2001 8 2003 3.75 2004 6.875 2005 6.875 2006 6.875 2007 7.8740157480315 2008 7.8740157480315 2010 12.5 2011 12.5 2012 17.4863387978142 2013 17.4863387978142 2014 20.5298013245033 2015 20.5298013245033 2016 20.5298013245033 2017 19.205298013245 2018 19.205298013245 2019 15.8940397350993 2020 17.8807947019868 2021 17.8807947019868 2022 18.5430463576159 2023 18.5430463576159