Frequencies for first 10,000 rows of exp_dt_num variable in drug2007q1 dataset :

 Expiration |
date of the |
      drug. |
 (YYYYMMDD) |      Freq.     Percent        Cum.
------------+-----------------------------------
  01jul2005 |          1        0.01        0.01
  01feb2006 |          1        0.01        0.02
  31mar2006 |          1        0.01        0.03
  22may2006 |          1        0.01        0.04
  06jan2007 |          1        0.01        0.05
  05mar2007 |          1        0.01        0.06
  06apr2007 |          1        0.01        0.07
  01may2007 |          1        0.01        0.08
  01jun2007 |          2        0.02        0.10
  30aug2007 |          1        0.01        0.11
  01sep2007 |          1        0.01        0.12
  30sep2007 |          1        0.01        0.13
  31oct2007 |          1        0.01        0.14
  22nov2007 |          1        0.01        0.15
  14dec2007 |          1        0.01        0.16
  19dec2007 |          1        0.01        0.17
  22dec2007 |          1        0.01        0.18
  28dec2007 |          1        0.01        0.19
  01jan2008 |          1        0.01        0.20
  31mar2008 |          1        0.01        0.21
  01apr2008 |          1        0.01        0.22
  30apr2008 |          1        0.01        0.23
  01may2008 |          2        0.02        0.25
  31may2008 |          3        0.03        0.28
  24jun2008 |          1        0.01        0.29
  01jul2008 |          2        0.02        0.31
  31aug2008 |          2        0.02        0.33
  31oct2008 |          1        0.01        0.34
  30nov2008 |          1        0.01        0.35
  01dec2008 |          2        0.02        0.37
  05feb2009 |          1        0.01        0.38
  01may2009 |          2        0.02        0.40
  31jul2009 |          1        0.01        0.41
          . |      9,959       99.59      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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