Year	%
1988	2.08
1993	2.97
1995	7.14
1996	1.43
1997	5.45
1998	2.9
1999	1.35
2000	2.28
2001	1.65
2002	0.7
2003	0.54
2004	0.51
2005	0.41
2006	0.43
2007	0.46
2008	0.43
2009	0.34
2010	0.38
2011	0.37
2012	0.36
2013	0.31
2014	0.37
2015	0.35
2016	0.38
2017	0.37
2018	0.35
2019	0.31
2020	0.34
2021	0.36