Year	%
1988	22.5
1989	22.51
1990	14.79
1992	14.72
1993	15.56
1994	15.22
1995	14.65
1996	8.53
1997	7.56
1998	6.37
1999	6.09
2000	3.77
2001	3.47
2002	2.62
2003	2.44
2004	2.86
2005	3.14
2006	3.1
2007	2.78
2008	4.1
2009	3.98
2010	3.96
2011	1.98
2012	1.85
2013	1.86
2015	1.75
2016	4.17
2017	1.66
2018	2.11
2019	1.68
2020	1.67
2021	1.73