Year	%
1997	21.79
1998	21.68
1999	21.68
2000	21.68
2001	21.68
2002	21.68
2003	21.68
2004	21.63
2005	21.62
2006	21.63
2007	21.63
2008	21.75
2009	21.75
2010	21.75
2011	21.75
2012	21.76
2013	21.76
2015	21.76
2020	21.82
2021	21.82