Year	Percent
1991	49.771
1992	50.306
1993	49.03
1994	48.637
1995	48.605
1996	47.756
1997	42.157
1998	40.051
1999	43.164
2000	44.21
2001	44.995
2002	39.282
2003	43.368
2004	38.822
2005	41.292
2006	43.529
2007	45.593
2008	46.209
2009	42.831
2010	36.723
2011	38.969
2012	39.351
2013	36.265
2014	36.135
2015	34.541
2016	36.6
2017	37.024
2018	37.696
2019	38.274
2020	38.358
2021	38.298
2022	38.191