Frequencies for first 10,000 rows of exp_dt variable in drug2014q1 dataset :

 Expiration |
date of the |
drug.Multip |
   le dates |
  possible. |      Freq.     Percent        Cum.
------------+-----------------------------------
  07jul2006 |          1        0.01        0.01
  20oct2007 |          1        0.01        0.02
  31jan2008 |          1        0.01        0.03
  30sep2012 |          1        0.01        0.04
          . |      9,996       99.96      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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