[Additional files](https://researchdatabase.minneapolisfed.org/downloads/d217qp51v "Additional files")
An updated version was published in _American Economic Review_ (Vol. 27, No. 2, May 2002, pp. 22-27), https://doi.org/10.1257/000282802320188934, and reprinted with permission as _Quarterly Review_ (Vol. 27, No. 2, Spring 2003), https://doi.org/10.21034/qr.2721.
A technical appendix for this paper is available as _Working Paper 619\_1_, https://doi.org/10.21034/wp.619_1.