Year	Percent
1991	4.43392
1992	4.43301
1993	4.62458
1994	6.33269
1995	7.28718
1996	6.1419
1997	5.44606
1998	5.79017
1999	6.39286
2000	6.56416
2001	6.9857
2002	7.59231
2003	7.96304
2004	8.43822
2005	8.48795
2006	8.4751
2007	8.46446
2008	8.40349
2009	8.19416
2010	8.04378
2011	7.8944
2012	7.76566
2013	7.60915
2014	7.60027
2015	7.68458
2016	8.22272
2017	8.11523
2018	7.99725
2019	8.06797