Year	Percent
1989	4.39627
1990	3.83344
1991	3.04323
1992	2.97263
1993	2.60927
1994	2.49262
1995	2.37413
1996	2.40293
1997	2.4307
1998	2.45306
1999	2.64517
2000	2.67117
2001	2.88446
2002	2.80126
2003	2.71202
2004	2.50695
2005	2.36008
2006	2.20034
2007	2.32415
2008	1.90775
2009	1.85652
2010	1.76538
2011	1.4438
2012	1.49816
2013	1.61332
2014	1.47308
2015	1.31645
2016	1.44222
2017	1.55429