Year	Percent
1991	27.958
1992	28.35
1993	28.981
1994	28.119
1995	27.448
1996	29.318
1997	30.222
1998	29.07
1999	32.372
2000	35.473
2001	25.935
2002	29.976
2003	33.794
2004	33.677
2005	32.032
2006	34.188
2007	36.07
2008	33.197
2009	29.777
2010	27.91
2011	26.634
2012	23.696
2013	20.849
2014	16.169
2015	13.134
2016	12.587
2017	14.35
2018	14.437
2019	14.143
2020	14.077
2021	14.112
2022	14.117