Year	Percent
1991	55.856
1992	55.588
1993	54.702
1994	54.12
1995	53.697
1996	53.41
1997	53.552
1998	54.19
1999	53.627
2000	53.985
2001	55.087
2002	57.092
2003	55.86
2004	57
2005	53.327
2006	53.68
2007	51.847
2008	49.509
2009	50.709
2010	47.336
2011	46.585
2012	47.747
2013	44.589
2014	43.685
2015	43.762
2016	44.228
2017	44.295
2018	44.108
2019	43.885
2020	43.672
2021	43.469
2022	43.283