Year	Percent
1991	37.545
1992	34.881
1993	32.523
1994	31.401
1995	30.73
1996	30.293
1997	29.319
1998	29.013
1999	28.039
2000	27.222
2001	28.367
2002	27.847
2003	26.988
2004	26.62
2005	26.486
2006	27.022
2007	26.809
2008	26.737
2009	24.063
2010	23.202
2011	23.891
2012	23.335
2013	22.912
2014	23.598
2015	23.748
2016	24.145
2017	23.925
2018	23.387
2019	22.974
2020	22.667
2021	22.372
2022	22.08