Year	Percent
1991	34.327
1992	35.05
1993	35.632
1994	34.546
1995	33.693
1996	33.855
1997	33.291
1998	33.534
1999	33.591
2000	32.668
2001	33.147
2002	32.609
2003	32.089
2004	31.95
2005	32.609
2006	30.817
2007	27.226
2008	26.63
2009	26.794
2010	26.604
2011	26.644
2012	26.131
2013	26.337
2014	26.82
2015	27.042
2016	27.351
2017	26.398
2018	26.02
2019	25.511
2020	25.029
2021	24.556
2022	24.061