Year	Percent
1971	1.06368
1972	1.04938
1973	1.0226
1974	1.02667
1975	1.01388
1976	1.00645
1977	1.01037
1978	1.01511
1979	0.98017
1980	0.97702
2001	1.04018
2002	1.06165
2003	1.07989
2004	1.109
2005	1.08921
2006	1.08173
2011	1.07268
2012	1.06032
2013	1.06518
2014	1.05033
2015	1.04459