Year	Percent
1991	32.735
1992	31.986
1993	32.096
1994	31.505
1995	31.147
1996	30.57
1997	30.524
1998	30.086
1999	30.155
2000	33.997
2001	34.216
2002	34.016
2003	33.521
2004	33.529
2005	33.348
2006	33.578
2007	33.305
2008	32.8
2009	33.192
2010	33.01
2011	33.182
2012	33.122
2013	33.051
2014	32.876
2015	33.001
2016	32.841
2017	33.067
2018	33.169
2019	33.236
2020	33.308
2021	33.527
2022	33.75