Year	Percent
1991	24.48897
1992	24.19166
1993	23.957
1994	27.41406
1995	24.39805
1996	25.21278
1997	20.49255
1998	23.13689
1999	21.70671
2000	21.0692
2001	20.66662
2002	20.33088
2003	19.78001
2004	19.00821
2005	17.76091
2006	16.98768
2007	16.47036
2008	15.77482
2009	15.23611
2010	14.60864
2011	13.83539
2012	13.15985
2013	12.57409
2014	11.83445
2015	11.24477
2016	10.62174
2017	10.12771
2018	11.09817
2019	9.57052