Year	Percent
1989	2.57626
1990	2.93378
1991	7.4426
1992	13.07185
1993	16.33149
1994	18.70663
1995	18.25736
1996	22.92628
1997	27.13318
1998	24.36874
1999	25.48768
2000	30.28566
2001	31.48576
2002	36.71125
2003	38.8601
2004	40.63244
2005	40.16741
2006	45.18717
2007	50.86628
2008	49.03789
2009	68.94984
2010	69.73944
2011	65.60862
2012	71.61975
2013	66.13812
2014	56.77313
2015	55.62995
2016	52.86652