Year	Percent
1991	43.177
1992	43.017
1993	42.909
1994	42.927
1995	31.808
1996	34.224
1997	32.803
1998	32.79
1999	32.468
2000	32.359
2001	31.8
2002	31.519
2003	31.031
2004	30.791
2005	30.717
2006	29.353
2007	29.401
2008	29.599
2009	29.494
2010	29.527
2011	29.638
2012	29.207
2013	28.967
2014	28.995
2015	28.723
2016	31.399
2017	31.798
2018	31.709
2019	31.599
2020	31.534
2021	31.473
2022	31.416