Year	Percent
1991	32.555
1992	33.459
1993	34.437
1994	34.609
1995	34.368
1996	34.949
1997	37.14
1998	37.392
1999	37.15
2000	37.604
2001	36.917
2002	37.548
2003	37.049
2004	38.728
2005	39.702
2006	40.85
2007	41.192
2008	41.051
2009	41.002
2010	40.926
2011	41.26
2012	42.376
2013	42.341
2014	41.44
2015	41.936
2016	42.238
2017	42.533
2018	42.705
2019	42.878
2020	42.993
2021	43.108
2022	43.218