Year	Percent
1991	33.803
1992	34.317
1993	35.027
1994	35.691
1995	36.157
1996	36.149
1997	36.874
1998	38.141
1999	38.339
2000	38.295
2001	40.339
2002	41.322
2003	42.523
2004	42.894
2005	44.589
2006	35.865
2007	30.514
2008	26.518
2009	31.216
2010	32.041
2011	32.046
2012	32.759
2013	32.964
2014	34.882
2015	37.372
2016	39.566
2017	43.306
2018	43.151
2019	43.07
2020	42.94
2021	42.818
2022	42.68