The data files used to generate the tabulations described above were the 2003 CPS ASEC supplement, the 2002 ACS, the 2001 SIPP panel, the 2002 Full-year Consolidated MEPS-HC, the 2003 NHIS, the 2003 PSID, the 2004 HRS, and the 2003 MCBS Cost and Use File. All but the 2003 MCBS are public use files, but NHIS income amounts are available only on an internal file that is restricted to on-site tabulations with prior approval and usage fees. We submitted a proposal, as required, to obtain access to the NHIS income data. We carried out our work with these data at the NCHS Research Data Center, located at NCHS headquarters in Hyattsville, Maryland, for which the study paid user fees. MCBS has no public use files, but allows protected off-site use with approval and has a standing agreement with ASPE, under which the study operated.