Year	Percent
1991	48.91
1992	49.53
1993	47.91
1994	46.59
1995	44.72
1996	43.35
1997	44.95
1998	43.56
1999	41.4
2000	40.16
2001	38.73
2002	37.86
2003	35.38
2004	33.07
2005	30.96
2006	29.18
2007	27.53
2008	26.01
2009	25.03
2010	22.48
2011	34.34
2012	26.78
2013	20.61
2014	17.79
2015	19.46
2016	21.55
2017	23.09
2018	25.53
2019	26.81