Year	Percent
1991	61.897
1992	60.833
1993	57.113
1994	60.416
1995	59.844
1996	57.597
1997	54.319
1998	57.74
1999	56.131
2000	53.352
2001	53.016
2002	52.002
2003	54.06
2004	53.439
2005	52.781
2006	53.86
2007	56.405
2008	56.128
2009	53.508
2010	55.244
2011	56.236
2012	56.669
2013	55.643
2014	54.097
2015	55.191
2016	54.423
2017	54.52
2018	54.62
2019	54.64
2020	54.54
2021	54.361
2022	54.038