Year	Percent
1991	16.372
1992	16.842
1993	15.804
1994	16.014
1995	14.617
1996	13.844
1997	19.223
1998	16.673
1999	15.167
2000	13.078
2001	12.369
2002	12.086
2003	10.099
2004	9.881
2005	7.996
2006	8.442
2007	7.781
2008	5.761
2009	6.18
2010	5.728
2011	5.343
2012	4.849
2013	4.902
2014	4.47
2015	5.044
2016	5.06
2017	4.921
2018	4.719
2019	4.486
2020	4.264
2021	4.061
2022	3.88