Year	Percent
1991	44.85
1992	46.401
1993	46.421
1994	49.508
1995	50.186
1996	51.947
1997	52.627
1998	52.725
1999	52.445
2000	51.934
2001	53.118
2002	52.931
2003	53.05
2004	57.293
2005	55.078
2006	54.427
2007	55.348
2008	56.782
2009	57.983
2010	58.132
2011	57.075
2012	57.18
2013	57.921
2014	57.68
2015	57.394
2016	57.692
2017	57.635
2018	57.803
2019	58.042
2020	58.297
2021	58.514
2022	58.695