Year	Percent
1991	10.98872
1992	10.8095
1993	10.62391
1994	10.3662
1995	9.77614
1996	9.20006
1997	8.64334
1998	8.54006
1999	9.42113
2000	8.70542
2001	9.13048
2002	8.82358
2003	7.8649
2004	7.32374
2005	6.91403
2006	6.97049
2007	6.92441
2008	6.64801
2009	6.4904
2010	6.73747
2011	6.90895
2012	6.75329
2013	6.44825
2014	6.24751
2015	6.13578
2016	6.60467
2017	6.33725
2018	5.90875
2019	5.82428