Frequencies for first 10,000 rows of exp_dt_num variable in drug2010q2 dataset :

 Expiration |
date of the |
      drug. |
 (YYYYMMDD) |      Freq.     Percent        Cum.
------------+-----------------------------------
  01sep2009 |          1        0.01        0.01
  01feb2010 |          1        0.01        0.02
  20aug2010 |          1        0.01        0.03
  30sep2010 |          1        0.01        0.04
  01nov2010 |          2        0.02        0.06
  07jan2011 |          1        0.01        0.07
  08jan2011 |          1        0.01        0.08
  31jan2011 |          1        0.01        0.09
  23feb2011 |          1        0.01        0.10
  28feb2011 |          1        0.01        0.11
  16mar2011 |          1        0.01        0.12
  31mar2011 |          1        0.01        0.13
  30apr2011 |          1        0.01        0.14
  30jun2011 |          1        0.01        0.15
  01jul2011 |          1        0.01        0.16
  31jul2011 |          1        0.01        0.17
  30sep2011 |          2        0.02        0.19
  01mar2012 |          2        0.02        0.21
  01may2012 |          4        0.04        0.25
  12aug2012 |          1        0.01        0.26
  31may2013 |          1        0.01        0.27
  01jun2013 |          1        0.01        0.28
  31mar2015 |          1        0.01        0.29
          . |      9,971       99.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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