Year	%
1997	1.56
1998	1.44
1999	1.88
2000	2.34
2001	2.65
2002	2.28
2003	1.93
2004	1.86
2005	2.78
2006	3.16
2007	3.02
2008	3.89
2009	4.75
2010	3.93
2011	3.68
2012	3.97
2013	4.46
2015	4.97
2016	5.31
2017	5.28
2018	5.2
2019	5.33
2020	4.92
2021	4.95