Year	Percent
1991	30.289
1992	30.669
1993	30.766
1994	27.793
1995	28.206
1996	27.092
1997	28.211
1998	28.099
1999	28.725
2000	27.151
2001	27.914
2002	27.767
2003	27.655
2004	27.483
2005	27.478
2006	30.631
2007	33.806
2008	34.976
2009	33.942
2010	33.807
2011	34.05
2012	34.072
2013	34.662
2014	34.799
2015	35.379
2016	35.085
2017	35.012
2018	34.82
2019	34.602
2020	34.374
2021	34.18
2022	34.005