Year	Percent
1991	2.17453
1993	6.04132
1995	4.4512
1996	4.15212
1997	3.67068
1998	3.09563
1999	2.34448
2000	2.44792
2001	2.26739
2002	2.40439
2003	2.52445
2004	2.10649
2005	1.90582
2006	1.62024
2007	1.40245
2008	1.05235
2009	1.57271
2010	2.07629
2011	1.7146
2012	1.68866
2013	1.76681
2014	1.88422
2015	2.08813
2016	1.92961
2017	1.82987