Year	Percent
1991	6.73164
1992	6.41888
1993	5.96685
1994	5.80729
1995	5.70338
1996	5.51593
1997	5.3663
1998	5.29968
1999	5.21337
2000	5.09054
2001	4.91391
2002	4.7206
2003	4.63819
2004	4.55819
2005	4.45935
2006	4.38476
2007	4.3139
2008	4.24652
2009	4.2115
2010	4.0665
2011	3.96698
2012	3.86603
2013	3.74662
2014	3.68977
2015	3.63346
2016	3.50212
2017	3.44078
2018	3.49428
2019	3.3757