Year	Percent
1991	31.542
1992	31.934
1993	31.582
1994	31.37
1995	32.933
1996	34.167
1997	33.193
1998	32.279
1999	28.612
2000	28.09
2001	28.465
2002	29.181
2003	27.812
2004	26.813
2005	26.183
2006	25.347
2007	25.132
2008	25.905
2009	25.698
2010	25.68
2011	25.705
2012	25.749
2013	25.823
2014	24.199
2015	24.046
2016	23.353
2017	23.151
2018	23.122
2019	22.685
2020	22.548
2021	22.282
2022	22.745