Year	%
1997	29.31
1998	29.27
2000	29.27
2001	29.27
2003	30.27
2004	30.2
2005	30.15
2006	30.15
2007	30.3
2008	30.3
2009	30.3
2010	30.3
2011	30.29
2012	31.99
2014	31.99
2015	31.72
2017	31.72
2018	31.71
2019	31.71
2020	31.71
2021	31.71