Year	Percent
1991	25.605
1992	21.538
1993	19.157
1994	33.45
1995	32.759
1996	45.941
1997	36.464
1998	36.909
1999	34.041
2000	39.558
2001	36.256
2002	36.585
2003	36.617
2004	36.955
2005	36.922
2006	30.885
2007	30.199
2008	30.812
2009	28.237
2010	27.658
2011	20.551
2012	22.57
2013	25.334
2014	25.081
2015	25.372
2016	25.278
2017	25.571
2018	25.528
2019	25.498
2020	25.413
2021	25.551
2022	25.565