Year	Percent
1991	51.21
1992	42.16
1993	38.06
1994	35.401
1995	30.689
1996	28.404
1997	34.136
1998	34.582
1999	37.134
2000	37.093
2001	38.077
2002	36.493
2003	37.033
2004	36.853
2005	40.768
2006	43.143
2007	45.2
2008	45.02
2009	37.723
2010	37.396
2011	39.327
2012	40.711
2013	38.819
2014	39.65
2015	38.308
2016	39.909
2017	40.095
2018	40.239
2019	40.059
2020	39.617
2021	39.159
2022	38.729