Year	Percent
1991	34.255
1992	32.869
1993	32.059
1994	32.852
1995	32.269
1996	31.44
1997	31.102
1998	31.291
1999	31.626
2000	29.282
2001	30.625
2002	28.209
2003	28.862
2004	27.909
2005	28.791
2006	27.577
2007	26.111
2008	26.087
2009	26.778
2010	26.336
2011	25.476
2012	24.729
2013	23.839
2014	22.968
2015	22.755
2016	22.79
2017	22.725
2018	22.571
2019	22.213
2020	21.883
2021	21.56
2022	21.153