Frequencies for first 10,000 rows of exp_dtstr variable in drug2013q1 dataset :

   Expiration date of the drug.Multiple |
                        dates possible. |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                        |      9,996       99.96       99.96
                               20090801 |          1        0.01       99.97
                               20120731 |          1        0.01       99.98
                                 201506 |          1        0.01       99.99
                                 201712 |          1        0.01      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Apr 2017