Year	Percent
1991	1.219
1992	0.968
1993	1.513
1994	2.091
1995	2.551
1996	2.761
1997	4.206
1998	4.143
1999	9.227
2000	8.81
2001	7.456
2002	7.32
2003	6.978
2004	7.238
2005	7.552
2006	7.3
2007	7.253
2008	7.206
2009	7.353
2010	6.793
2011	7.071
2012	6.901
2013	7.271
2014	7.209
2015	7.224
2016	7.505
2017	7.722
2018	7.708
2019	7.701
2020	7.7
2021	7.698
2022	7.696