Year	Percent
1991	55
1992	54.173
1993	53.539
1994	52.064
1995	50.99
1996	50.145
1997	49.094
1998	48.116
1999	47.663
2000	46.514
2001	45.86
2002	45.227
2003	45.004
2004	44.26
2005	43.556
2006	42.856
2007	41.774
2008	41.311
2009	41.239
2010	40.902
2011	40.548
2012	40.31
2013	40.138
2014	40.012
2015	39.814
2016	39.433
2017	39.355
2018	39.286
2019	39.216
2020	39.146
2021	39.078
2022	39.009