Year	Percent
1991	32.57
1992	26.768
1993	22.86
1994	32.204
1995	32.659
1996	30.859
1997	32.136
1998	29.251
1999	24.865
2000	32.599
2001	31.208
2002	29.676
2003	27.825
2004	29.722
2005	28.671
2006	27.007
2007	26.924
2008	33.857
2009	32.167
2010	32.44
2011	30.082
2012	30.355
2013	32.444
2014	31.722
2015	30.129
2016	31.423
2017	31.502
2018	31.638
2019	31.614
2020	31.749
2021	31.722
2022	31.697