Year	Percent
1991	61.513
1992	61.013
1993	60.384
1994	59.04
1995	59.007
1996	59.079
1997	58.475
1998	57.218
1999	55.408
2000	53.398
2001	53.437
2002	52.691
2003	53.219
2004	54.197
2005	54.05
2006	54.068
2007	56.243
2008	57.093
2009	55.576
2010	53.222
2011	51.708
2012	49.595
2013	47.558
2014	49.24
2015	50.145
2016	50.752
2017	51.57
2018	52.447
2019	52.524
2020	52.297
2021	51.993
2022	51.655