Year	Percent
1991	14.117
1992	13.507
1993	12.949
1994	12.761
1995	12.634
1996	11.728
1997	10.989
1998	10.274
1999	8.93
2000	8.772
2001	8.765
2002	8.697
2003	8.513
2004	8.176
2005	8.871
2006	8.118
2007	7.636
2008	7.492
2009	8.026
2010	7.398
2011	6.192
2012	6.211
2013	6.365
2014	5.985
2015	5.712
2016	6.038
2017	6.112
2018	5.932
2019	5.753
2020	5.582
2021	5.438
2022	5.285