Year	Percent
1993	16.8
1994	17
1995	15.83
1996	16.33
1997	20.47
1998	21.6
1999	18.09
2000	16.49
2002	20.39
2003	22.18
2004	20.97
2005	18.7
2006	16
2007	14
2008	12.72
2009	15.37
2011	18.86
2012	19.06
2013	22.21
2017	18.86
2018	19.08
2019	15.32