Frequencies for first 10,000 rows of exp_dtstr variable in drug2017q2 dataset :

             Expiration date of the |
      drug.Multiple dates possible. |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                                    |     10,000      100.00      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 8 Feb 2018