Year	Percent
1992	12.961
1993	13.502
1994	15.365
1995	17.764
1996	18.347
1997	23.083
1998	26.705
1999	22.489
2000	19.5
2001	17.039
2002	14.468
2003	16.53
2004	16.054
2005	14.405
2006	15.741
2007	14.46
2008	13.209
2009	18.124
2010	16.8163
2011	15.2333
2012	14.5392
2013	13.352
2014	13.4292
2015	15.3704
2016	15.8403
2017	15.7395