_dta:
  1.  by Jean Roth , jroth@nber.org , 18 Nov 2015
  2.  Source: 2012/07/packages.txt
  3.  File description: http://www.fda.gov/Drugs/InformationOnDrugs/ucm142454.htm
  4.  MAY OCCUR MULTIPLE TIMES PER LISTING SEQ NO
  5.  Stores packages for an individual listing.
  6.  The packages table includes all packages for a corresponding listing.
  7.  The PKGCODE field contains the last one or two digit segment of the NDC.

listing_seq_no:
  1.  LISTING_SEQ_NO NOT NULL NUM(7) COL: 1-7
  2.  Linking field to LISTINGS.

pkgcode:
  1.  PKGCODE NULL CHAR(2) COL: 9-10
  2.  The package code portion of NDC code. The package code is the last segment of the
      NDC.

packsize:
  1.  PACKSIZE NOT NULL CHAR(25) COL: 12-36
  2.  The unit or number of units which make up a package.

packtype:
  1.  PACKTYPE NOT NULL CHAR(25) COL: 38-62
  2.  Package type, i.e., box, bottle, vial, plastic, or glass.

  obs:       183,464                          
 vars:             4                          18 Nov 2015 23:13
 size:    10,273,984                          (_dta has notes)
---------------------------------------------------------------------------------------
              storage   display    value
variable name   type    format     label      variable label
---------------------------------------------------------------------------------------
listing_seq_no  long    %12.0g              * FDA generated unique identification
                                                number for each product
pkgcode         str2    %9s                 * The package code portion of NDC code
packsize        str25   %25s                * The unit or number of units which make up
                                                a package
packtype        str25   %25s                * Package type, i.e., box, bottle, vial,
                                                plastic, or glass.
                                            * indicated variables have notes
---------------------------------------------------------------------------------------
Sorted by:  listing_seq_no  pkgcode  packsize  packtype