Year	Percent
1991	41.01
1992	39.46
1993	37.286
1994	38.017
1995	34.788
1996	32.16
1997	33.23
1998	30.413
1999	31.498
2000	30.166
2001	31.17
2002	29.059
2003	28.277
2004	27.436
2005	25.544
2006	25.191
2007	25.618
2008	22.177
2009	19.559
2010	19.837
2011	20.34
2012	19.518
2013	18.093
2014	16.33
2015	19.122
2016	18.056
2017	17.854
2018	17.621
2019	17.375
2020	17.149
2021	16.903
2022	16.738