Year	Percent
1991	53.546
1992	54.264
1993	52.489
1994	52.949
1995	52.834
1996	54.094
1997	52.786
1998	48.783
1999	49.093
2000	50.427
2001	51.972
2002	53.392
2003	51.014
2004	47.643
2005	51.024
2006	49.209
2007	47.028
2008	48.337
2009	50.048
2010	51.345
2011	50.5
2012	49.969
2013	47.633
2014	39.826
2015	41
2016	40.56
2017	40.6
2018	40.345
2019	39.697
2020	39.204
2021	38.489
2022	37.791