Year	%
1988	5.84
1989	5.8
1990	7.59
1991	6.79
1992	7.15
1993	7.01
1994	6.82
1995	6.4
1996	5.03
1997	5.06
1998	4.11
1999	3.66
2000	3.42
2001	3.64
2002	3.86
2003	3.82
2004	3.56
2005	3.53
2006	3.49
2007	3.36
2008	3.36
2009	3.39
2010	3.38
2011	3.42
2012	3.36
2013	3.39
2014	3.42
2015	3.43
2016	3.39
2017	3.47
2018	3.42
2019	3.39
2020	3.23
2021	2.9