Year	Percent
1991	28.612
1992	27.483
1993	29.353
1994	26.933
1995	22.281
1996	20.916
1997	21.041
1998	21.858
1999	21.899
2000	19.74
2001	21.378
2002	20.434
2003	19.809
2004	18.207
2005	18.093
2006	17.807
2007	18.111
2008	18.027
2009	16.391
2010	14.875
2011	16.328
2012	16.786
2013	15.423
2014	15.364
2015	15.032
2016	14.55
2017	14.64
2018	14.402
2019	14.165
2020	13.891
2021	13.63
2022	13.372