Year	Percent
1991	28.692
1992	28.732
1993	28.399
1994	28.206
1995	28.281
1996	28.123
1997	28.02
1998	14.043
1999	13.849
2000	13.779
2001	13.694
2002	13.578
2003	13.485
2004	13.422
2005	13.38
2006	13.336
2007	13.383
2008	13.303
2009	13.325
2010	13.351
2011	13.359
2012	13.337
2013	13.349
2014	13.343
2015	13.33
2016	13.335
2017	13.375
2018	13.35
2019	13.318
2020	13.282
2021	13.246
2022	13.21