Year	Percent
1991	32.146
1992	29.887
1993	25.597
1994	25.754
1995	26.141
1996	24.452
1997	21.659
1998	17.22
1999	15.338
2000	15.134
2001	14.704
2002	16.101
2003	22.174
2004	14.512
2005	18.748
2006	24.02
2007	12.36
2008	17.786
2009	17.256
2010	17.057
2011	16.877
2012	14.701
2013	14.103
2014	14.683
2015	14.241
2016	12.569
2017	12.816
2018	13.164
2019	12.661
2020	12.287
2021	11.987
2022	11.662