_dta:
  1.  date_changes20092 set up by Jean Roth , jroth@nber.org , 8 Jan 2016

ndc:
  1.  The National Drug Code (NDC) serves as a universal product identifier for human drugs and biologics.
  2.  Each NDC must be reported as an 11-digit code unique to the manufacturer of the specific drug or product.

ndc13:
  1.  The National Drug Code (NDC) serves as a universal product identifier for human drugs and biologics.
  2.  Each NDC must be reported as an 11-digit code unique to the manufacturer of the specific drug or product.

  obs:            37                          
 vars:             5                          8 Jan 2016 16:51
 size:         1,665                          (_dta has notes)
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              storage   display    value
variable name   type    format     label      variable label
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ndc             str11   %11s                * National Drug Code (NDC)
ndc13           str13   %13s                * National Drug Code (NDC) with Dashes
change          str17   %17s                  Change
olddate         int     %td..                 Old Date
newdate         int     %td..                 New Date
                                            * indicated variables have notes
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Sorted by: ndc