Year	Percent
1991	15.879
1992	15.358
1993	15.522
1994	15.72
1995	15.069
1996	14.415
1997	13.952
1998	14.554
1999	16.754
2000	20.182
2001	20.201
2002	20.141
2003	20.495
2004	24.181
2005	22.139
2006	21.663
2007	23.279
2008	19.08
2009	20.639
2010	18.109
2011	19.481
2012	22.306
2013	15.988
2014	16.133
2015	13.966
2016	14.674
2017	14.423
2018	14.183
2019	13.863
2020	13.559
2021	13.288
2022	13.011