Year	Percent
1991	27.549
1992	27.147
1993	26.715
1994	26.301
1995	25.931
1996	25.701
1997	25.505
1998	25.342
1999	25.18
2000	25.018
2001	25.083
2002	25.087
2003	25.066
2004	25.074
2005	25.135
2006	25.98
2007	26.858
2008	27.755
2009	28.444
2010	29.74
2011	31.542
2012	34.685
2013	34.854
2014	34.932
2015	34.934
2016	34.425
2017	34.115
2018	34.058
2019	33.931
2020	33.838
2021	33.789
2022	33.738