Year	Percent
1991	16.648
1992	16.523
1993	16.061
1994	17.023
1995	19.595
1996	20.174
1997	21.06
1998	22.71
1999	23.007
2000	20.66
2001	20.687
2002	24.76
2003	25.095
2004	25.145
2005	28.054
2006	27.567
2007	25.404
2008	26.856
2009	33.062
2010	30.187
2011	25.787
2012	28.701
2013	29.494
2014	29.289
2015	33.59
2016	33.409
2017	33.278
2018	33.05
2019	32.799
2020	32.542
2021	32.293
2022	32.054