1 The authors would like to thank Magnus Andersson, Jacopo Cimadomo, Fédéric Holm-Hadulla, Philipp Rother, Ad van Riet, Jürgen von Hagen and participants of an ECB seminar for helpful comments on previous versions of the paper. We are very grateful to Alex Isar for excellent research assistance and inputs. Abstract 4 Non-technical summary 5