Frequencies for first 10,000 rows of exp_dt_num variable in drug2007q2 dataset :

 Expiration |
date of the |
      drug. |
 (YYYYMMDD) |      Freq.     Percent        Cum.
------------+-----------------------------------
  01may2007 |          1        0.01        0.01
  11mar2008 |          1        0.01        0.02
  01may2008 |          1        0.01        0.03
  01jun2008 |          1        0.01        0.04
  30jun2008 |          1        0.01        0.05
  01oct2008 |          1        0.01        0.06
          . |      9,994       99.94      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Dec 2015