Year	Percent
1991	36.195
1992	37.298
1993	38.71
1994	38.339
1995	40.897
1996	39.626
1997	38.318
1998	39.488
1999	40.155
2000	40.062
2001	39.683
2002	38.074
2003	36.512
2004	38.282
2005	38.133
2006	37.882
2007	34.3
2008	35.967
2009	34.169
2010	32.689
2011	35.865
2012	36.04
2013	35.424
2014	33.504
2015	32.69
2016	29.955
2017	29.818
2018	29.601
2019	29.349
2020	28.881
2021	28.146
2022	27.41