Year	Percent
1991	57.376
1992	56.621
1993	57.066
1994	58.134
1995	58.677
1996	57.563
1997	57.669
1998	58.324
1999	58.451
2000	58.933
2001	56.122
2002	53.508
2003	51.592
2004	51.568
2005	51.333
2006	52.573
2007	50.881
2008	48.756
2009	43.49
2010	41.52
2011	42.311
2012	43.126
2013	43.598
2014	44.832
2015	45.805
2016	46.925
2017	47.11
2018	47.046
2019	46.562
2020	46.193
2021	45.755
2022	45.335