Year	Percent
1991	34.642
1992	36.055
1993	34.147
1994	32.695
1995	31.807
1996	30.97
1997	29.11
1998	28.499
1999	28.536
2000	28.682
2001	28.372
2002	27.217
2003	28.362
2004	25.343
2005	25.037
2006	25.501
2007	24.595
2008	25.931
2009	27.629
2010	28.022
2011	24.435
2012	25.661
2013	25.417
2014	25.483
2015	25.525
2016	25.56
2017	25.915
2018	25.619
2019	25.254
2020	24.953
2021	24.73
2022	24.463