Frequencies for first 10,000 rows of exp_dtstr variable in drug2013q2 dataset :

   Expiration date of the drug.Multiple |
                        dates possible. |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                        |      9,989       99.89       99.89
                                   2009 |          1        0.01       99.90
                               20110630 |          1        0.01       99.91
                                 201202 |          1        0.01       99.92
                               20130430 |          1        0.01       99.93
                               20130731 |          1        0.01       99.94
                                 201309 |          1        0.01       99.95
                               20130930 |          2        0.02       99.97
                               20131031 |          1        0.01       99.98
                               20140228 |          1        0.01       99.99
                               20140531 |          1        0.01      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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