Year	Percent
1991	15.963
1992	15.466
1993	12.509
1994	12.364
1995	11.986
1996	11.606
1997	11.24
1998	11.099
1999	11.853
2000	11.997
2001	11.8
2002	12.468
2003	11.589
2004	10.847
2005	11.323
2006	10.736
2007	11.01
2008	10.281
2009	9.712
2010	10.074
2011	9.671
2012	8.631
2013	8.57
2014	8.316
2015	8.36
2016	8.171
2017	8.303
2018	8.238
2019	8.128
2020	8.029
2021	7.921
2022	7.822