| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year | | 2004 | 0.76 | 0.76 | 0.77 | 0.78 | 0.80 | 0.82 | 0.83 | 0.84 | 0.86 | 0.89 | 0.91 | 0.91 | 0.83 | | 2005 | 0.91 | 0.91 | 0.93 | 0.94 | 0.94 | 0.95 | 0.96 | 0.96 | 0.97 | 0.98 | 0.99 | 1.01 | 0.95 | | 2006 | 1.03 | 1.04 | 1.04 | 1.05 | 1.06 | 1.07 | 1.08 | 1.07 | 1.07 | 1.07 | 1.07 | 1.07 | 1.06 | | 2007 | 1.07 | 1.05 | 1.05 | 1.05 | 1.06 | 1.07 | 1.06 | 1.05 | 1.04 | 1.02 | 1.00 | 0.98 | 1.04 | | 2008 | 0.98 | 0.97 | 0.95 | | | | | | | | | | |
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