Year	%
1997	15.6
1999	15.66
2000	3.13
2001	3.09
2002	2.95
2003	2.3
2004	2.1
2005	2.13
2006	1.89
2007	1.6
2008	2.77
2009	2.72
2010	2.68
2012	2.57
2013	2.59
2018	4.64
2019	7.82
2020	3.63
2021	3.62