Year	Percent
1992	3.779
1993	3.546
1994	5.005
1995	5.231
1996	6.55
1997	8.096
1998	9.17
1999	9.654
2000	7.451
2001	5.943
2002	5.043
2003	4.646
2004	5.112
2005	4.383
2006	3.925
2007	3.545
2008	4.59
2009	6.299
2010	5.6207
2011	5.1213
2012	3.9669
2013	4.1388
2014	4.3295
2015	4.3208
2016	4.3722
2017	4.3965