Frequencies for first 10,000 rows of exp_dtstr variable in drug2013q4 dataset :

   Expiration date of the drug.Multiple |
                        dates possible. |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                        |      9,991       99.91       99.91
                               20080131 |          1        0.01       99.92
                               20090430 |          1        0.01       99.93
                               20090930 |          1        0.01       99.94
                               20100228 |          1        0.01       99.95
                               20100430 |          1        0.01       99.96
                                 201101 |          1        0.01       99.97
                               20110603 |          1        0.01       99.98
                                 201203 |          1        0.01       99.99
                               20120630 |          1        0.01      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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