Year	%
1989	2.89
1990	2.81
1991	2.79
1992	2.81
1993	2.65
1995	3.04
1996	3.25
1997	3.41
1998	3.7
1999	3.15
2000	3.1
2001	3.21
2002	3.31
2003	3.01
2004	2.89
2005	2.7
2006	2.67
2007	2.92
2008	2.54
2009	2.54
2010	2.45
2011	2.63
2012	2.53
2013	2.49
2014	2.53
2015	2.43
2016	2.44
2017	6.64
2018	5.96
2019	39.52
2020	2.72
2021	2.56