Year	Percent
1988	3.97
1989	2.97
1990	3.08
1991	2.49
1992	2.74
1993	2.77
1994	2.31
1995	2.46
1996	1.56
1997	1.52
1998	1.84
1999	1.95
2000	2.15
2001	2.28
2002	3.52
2003	3.72
2004	3.64
2005	3.93
2006	3.57
2007	3.51
2008	4.36
2009	5.64
2010	5.01
2011	4.33
2012	3.88
2013	4.66
2014	5.99
2015	6.67
2016	6.18
2017	6.49
2018	6.75
2019	8.04
2020	7.19