Year	Percent
1991	30.765
1992	31.545
1993	32.449
1994	31.506
1995	31.487
1996	30.455
1997	30.305
1998	30.373
1999	30.751
2000	30.157
2001	31.909
2002	30.896
2003	29.883
2004	28.801
2005	26.942
2006	26.138
2007	23.427
2008	29.09
2009	27.803
2010	26.691
2011	26.295
2012	25.711
2013	26.285
2014	25.403
2015	25.954
2016	26.481
2017	26.599
2018	26.679
2019	26.549
2020	26.194
2021	26.144
2022	26.11