Year	Percent
1991	30.37
1992	31.253
1993	32.711
1994	30.93
1995	32.01
1996	31.404
1997	30.324
1998	30.062
1999	29.893
2000	30.369
2001	31.191
2002	32.988
2003	30.021
2004	28.919
2005	28.599
2006	27.627
2007	26.856
2008	26.852
2009	27.068
2010	27.321
2011	27.276
2012	26.841
2013	28.791
2014	28.503
2015	28.375
2016	28.422
2017	28.48
2018	28.403
2019	28.334
2020	28.283
2021	28.229
2022	28.186