Year	Percent
1991	16.197
1992	16.272
1993	15.721
1994	14.112
1995	14.173
1996	13.186
1997	13.595
1998	13.311
1999	12.943
2000	12.672
2001	11.855
2002	11.461
2003	11.222
2004	11.113
2005	11.224
2006	11.543
2007	12.083
2008	11.21
2009	13.089
2010	12.562
2011	12.067
2012	11.541
2013	10.121
2014	10.621
2015	12.61
2016	12.637
2017	13.353
2018	13.727
2019	13.807
2020	13.845
2021	13.561
2022	13.451