2005-11-04 On 2005-03-14 new files were added to one
or more datasets. These files included additional setup files as well
as one or more of the following: SAS program, SAS transport, SPSS portable,
and Stata system files. The metadata record was revised 2005-11-04 to
reflect these additions.
2006-03-30 File CB9972.ALL.PDF was removed from any previous datasets and flagged as a study-level file, so that it will accompany all downloads.
1998-10-05 The card image data were converted to logical
record length format, and SAS and SPSS data definition statements have
been added to this collection. Also, the codebook has been converted
to a PDF file.