Year	Percent
1991	55.853
1992	55.653
1993	53.565
1994	50.722
1995	49.328
1996	48.549
1997	46.671
1998	45.21
1999	47.905
2000	49.692
2001	49.612
2002	51.026
2003	50.79
2004	51.265
2005	51.964
2006	52.391
2007	53.516
2008	53.244
2009	52.414
2010	52.65
2011	53.465
2012	54.034
2013	53.831
2014	54.033
2015	53.741
2016	53.885
2017	53.782
2018	53.543
2019	53.302
2020	53.003
2021	52.689
2022	52.403