Year	Percent
1991	56.026
1992	54.629
1993	55.329
1994	58.628
1995	62.385
1996	61.654
1997	60.24
1998	57.11
1999	56.565
2000	56.199
2001	57.973
2002	58.758
2003	58.397
2004	59.741
2005	59.459
2006	61.108
2007	60.59
2008	58.398
2009	53.92
2010	51.537
2011	51.007
2012	50.605
2013	51.205
2014	54.129
2015	54.982
2016	56.289
2017	56.343
2018	55.679
2019	54.945
2020	54.454
2021	53.897
2022	53.233