Year	Percent
1988	2.42226
1989	1.99232
1990	2.393
1991	2.87735
1992	2.29032
1993	3.61475
1994	3.78768
1995	5.81237
1996	6.01931
1997	5.79154
1998	8.47573
1999	10.19979
2000	13.74938
2001	10.25559
2002	12.00134
2003	12.56773
2004	11.8497
2005	10.57854
2006	10.96414
2007	7.36574
2008	9.20563
2009	10.61276
2010	10.09712
2011	9.75327
2012	9.07446
2013	7.53791
2014	10.31597
2015	10.9868
2016	11.44428
