Negative rates and inflation

Have negative interest rates boosted inflation? Here is a nice graph (source macro-man blog, HT FT alphaville)

Source: Macro-man blog

Not really. Explanations? Choose the chicken or the egg:

1) But for negative rates, inflation would have been even lower

2) We're living in a Fisher effect world. Lower rates lower inflation. (Which is arguably a good, if unintended, thing)