Year	Percent
1991	17.90356
1992	17.75404
1993	17.64813
1994	17.33203
1995	17.57986
1996	17.49682
1997	17.13712
1998	16.95695
1999	16.50563
2000	16.25174
2001	15.64575
2002	15.90569
2003	15.20843
2004	14.87463
2005	15.24644
2006	14.03509
2007	13.2651
2008	12.39204
2009	11.83725
2010	11.37229
2011	10.90527
2012	10.27896
2013	9.89738
2014	11.16015
2015	12.30729
2016	12.214
2017	12.57998
2018	12.39815
2019	11.7844