Year	%
1988	17.14
1989	13.72
1990	11.51
1992	9.9
1995	7.43
1996	7.71
1997	7.22
1998	6.59
1999	6.26
2000	4.98
2001	5.25
2002	5.07
2003	4.91
2004	4.55
2005	4.43
2006	4.52
2007	4.01
2008	4.08
2009	4.32
2010	4.28
2011	4.39
2012	4.55
2013	4.63
2014	2.73
2015	2.45
2016	4.65
2017	2.36
2018	2.26
2020	1.93
2021	1.15