We show the monthly development of government bond yields over years, thanks to a table from the ECB.
May 2014 to May 2015
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Click to expand, source ECB
May 2013 to May 2014
June 2014:Disinflation in the Euro zone depresses bond yields everywhere, 2014 versus 2013
July 2012 to July 2013
By July 2013, government bond yields of European safe-havens have risen compared the rates of July 2012, but the ones of crisis countries decreased:
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Click to expand, source ECB
The following was the data as of July 18th 2012, at the height of negative interest rates for safe-havens.
Links: Government Bonds on Financial Times and on Forexpros
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