Year	Percent
1995	27.61176
1996	30.72975
1997	31.31888
1998	29.48576
1999	30.45728
2000	36.50504
2001	38.66242
2002	37.67148
2003	38.89011
2004	39.45436
2005	39.29563
2006	39.66324
2007	39.00046
2008	38.47725
2009	34.52328
2010	37.63391
2011	40.31593
2012	41.51545
2013	42.79563
2014	45.31144
2015	48.22707
2016	49.01297
2017	51.26024