Year	%
1988	13.98
1990	12.23
1991	11.89
1993	17.3
1996	16.09
1997	11.05
1999	9.93
2000	9.59
2001	9.85
2002	8.47
2003	8.6
2004	9.63
2005	9.1
2006	8.67
2007	8.23
2008	7.82
2009	7.81
2010	7.52
2011	7.31
2012	7.33
2013	6.67
2014	6.61
2015	6.6
2016	6.74
2017	7
2018	7.09
2019	7.53
2020	7.49
2021	7.5