NBER Working Paper No. 20834
---- Acknowledgments ----
Conversations with Robert Willis inspired this paper. I would also like to thank participants at the Japanese Economic Review conference at Keio University. In addition to an honorarium associated with that conference, this work was supported by National Institute on Aging grants P01-AG026571 and R01-AG040787 to the University of Michigan. The views expressed herein are those of the author and do not necessarily reflect the views of the National Bureau of Economic Research.