Year	%
1988	20.85809
1989	9.694566
1990	14.41539
1991	16.12353
1992	13.31339
1993	11.52714
1994	8.344948
1995	12.49345
1996	12.53712
1997	11.52683
1998	11.77531
1999	12.13909
2000	10.28347
2001	11.33524
2002	10.51266
2003	8.078493
2004	8.734162
2005	6.894521
2006	7.733672
2007	8.509957
2008	8.515925
2009	7.075123
2010	8.215336
2011	7.566368
2012	6.872892
2013	7.540516
2014	6.937143
2015	6.445969
2016	7.172038
2017	6.101612