Year	Percent
1991	15.58598
1992	15.36747
1993	15.18964
1994	14.79888
1995	14.72573
1996	14.73689
1997	14.31605
1998	13.99372
1999	13.65596
2000	14.06033
2001	12.24261
2002	15.39124
2003	16.23669
2004	16.35713
2005	15.03261
2006	16.74199
2007	16.05584
2008	13.37014
2009	12.6039
2010	11.81078
2011	11.61885
2012	11.48316
2013	10.54488
2014	10.39898
2015	8.65758
2016	7.36082
2017	6.70999
2018	6.32096
2019	6.0472