Year	Percent
1990	31.76
1994	27.3
1998	33.19
2003	21.25
2004	28.09
2008	26.35
2012	33.49
2013	37.77
2014	34.28
2015	32.85
2016	31.81
2017	28.15
2018	24.17
2019	20.58