Year	Percent
1991	65.724
1992	67.469
1993	66.448
1994	66.742
1995	64.881
1996	62.853
1997	61.343
1998	56.52
1999	52.713
2000	53.118
2001	55.102
2002	55.243
2003	54.504
2004	55.958
2005	54.883
2006	54.661
2007	54.244
2008	54.293
2009	53.351
2010	54.037
2011	54.022
2012	53.516
2013	52.674
2014	49.622
2015	47.595
2016	46.98
2017	46.82
2018	46.56
2019	46.304
2020	46.475
2021	46.526
2022	46.453