Acknowledgements: The authors would like to express their gratitude to the anonymous referee and all those that have helped improve the quality of the paper. This research was supported in part by the Center for Economic Policy Studies at Princeton University. *The opinions expressed in this publication are entirely those of the authors and, in expressing their opinions, the authors are not acting as employees or agents of Merrill Lynch nor do the opinions expressed herein necessarily reflect those of Merrill Lynch. Merrill Lynch does not accept any liability for any content contained in the publication, or any errors.
