Frequencies for first 10,000 rows of exp_dtstr variable in drug2017q4 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 , 19 Jun 2018