Year	Percent
1991	38.29725
1992	39.66355
1993	53.68346
1994	62.25897
1995	56.28905
1996	50.29477
1997	47.46452
1998	48.4097
1999	36.825
2000	38.24523
2001	35.59334
2002	36.33756
2003	39.8218
2004	41.17305
2005	46.00113
2006	49.0416
2007	46.84277
2008	49.53617
2009	44.75945
2010	51.48664
2011	50.28703
2012	48.70692
2013	44.82373
2014	42.8817
2015	41.48881
2016	39.52204
2017	42.78147