Year	Percent
1991	42.71
1992	41.171
1993	39.78
1994	38.371
1995	37.865
1996	36.422
1997	35.115
1998	33.918
1999	32.869
2000	30.829
2001	29.98
2002	29.366
2003	28.747
2004	27.653
2005	27.365
2006	26.463
2007	25.751
2008	25.967
2009	26.57
2010	26.845
2011	28.09
2012	27.6
2013	27.456
2014	27.18
2015	27.043
2016	26.994
2017	26.913
2018	26.964
2019	26.976
2020	26.956
2021	26.931
2022	26.874