Year	%
1988	18.81
1989	15.08
1990	12.87
1992	10.92
1995	7.81
1996	8.17
1997	8.14
1998	8.5
1999	8.14
2000	8.05
2001	8
2002	7.85
2003	7.65
2004	7.28
2005	7.25
2006	7.33
2007	6.49
2008	7.31
2009	7.27
2010	7.31
2011	7.41
2012	7.22
2013	7.17
2014	3.05
2015	2.67
2016	7.29
2017	2.42
2018	2.38
2020	2.39
2021	2.14