2024 22,0% 2023 22,0% 2022 22,0% 2021 22,0% 2020 22,0% 2019 22,0% 2018 22,0% 2017 22,0% 2016 22,0% 2015 23,5% 2014 24,5% 2013 25% 2012 25% 2011 25% 2010 25% 2009 25% 2008 25% 2007 25% 2006 28% 2005 28% 2004 30% 2003 30% 2002 30% 2001 30% 2000 32% 1999 32% 1998 34% 1997 34% 1996 34% 1995 34% 1994 34% 1993 34% 1992 38% 1991 38% 1990 50% 1989 50% 1988 50% 1987 50%