Frequencies for first 10,000 rows of exp_dt variable in drug2010q4 dataset :

 Expiration |
date of the |
      drug. |
  (YYYYMMDD |
    format) |      Freq.     Percent        Cum.
------------+-----------------------------------
   2.01e+07 |          1        0.01        0.01
   2.01e+07 |          1        0.01        0.02
   2.01e+07 |          1        0.01        0.03
   2.01e+07 |          1        0.01        0.04
          . |      9,996       99.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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