Year	%
1988	2.1
1993	2.86
1995	10.24
1996	4.66
1997	8.34
1998	6.92
1999	4.47
2000	6.5
2001	5.07
2002	4.42
2003	4.08
2004	4.19
2005	4.39
2006	4.1
2007	4.32
2008	3.54
2009	3.4
2010	4.02
2011	4.13
2012	4.23
2013	4.12
2014	3.84
2015	3.94
2016	3.69
2017	3.62
2018	3.51
2019	3.24
2020	3.27
2021	3.49