Year	Percent
1991	1.53
1992	1.85
1993	2.235
1994	3.197
1995	5.123
1996	3.431
1997	2.167
1998	2.203
1999	1.745
2000	1.475
2001	1.749
2002	2.0117
2003	2.2958
2004	2.4457
2005	2.7298
2006	2.7179
2007	2.6808
2008	3.0623
2009	4.572
2010	4.5797
2011	4.3801
2012	4.1085
2013	4.1958
2014	4.0978
2015	3.6364
2016	3.3359
2017	2.8393