Year	Percent
1981	1.15897
1982	1.43759
1983	1.53438
1984	1.54392
1985	1.55983
1989	1.19933
1990	1.17631
1991	1.09405
1992	1.02155
1993	1.09549
1994	1.36044
1995	1.29885
1996	1.24214
1997	1.43567
2000	0.85525
2001	0.85504
2002	0.83963
2003	0.86356
2004	0.89674
2005	0.96131
2006	1.00892
2007	1.06614
2008	1.36761
2009	1.29156
2010	1.09779
2011	1.03694
2012	0.96715
2013	1.10175
2014	1.16712
2015	1.13154
2016	1.25597
2017	1.25308