Year	Percent
1991	18.233
1992	17.745
1993	16.181
1994	15.47
1995	15.606
1996	14.863
1997	14.109
1998	13.34
1999	13.025
2000	12.974
2001	12.307
2002	11.961
2003	11.293
2004	10.873
2005	10.755
2006	10.241
2007	10.478
2008	9.992
2009	10.074
2010	10.443
2011	10.513
2012	10.349
2013	10.339
2014	10.187
2015	9.752
2016	9.543
2017	9.613
2018	9.303
2019	9.083
2020	8.853
2021	8.615
2022	8.382