Frequencies for first 10,000 rows of exp_dt_num variable in drug2005q4 dataset :

 Expiration |
date of the |
      drug. |
 (YYYYMMDD) |      Freq.     Percent        Cum.
------------+-----------------------------------
  30nov1998 |          2        0.02        0.02
  31oct2003 |          1        0.01        0.03
  01apr2004 |          2        0.02        0.05
  01aug2004 |          1        0.01        0.06
  01dec2004 |          1        0.01        0.07
  11feb2005 |          1        0.01        0.08
  01apr2005 |          2        0.02        0.10
  01jul2005 |          1        0.01        0.11
  01aug2005 |          1        0.01        0.12
  01oct2005 |          2        0.02        0.14
  27nov2005 |          1        0.01        0.15
  31dec2005 |          1        0.01        0.16
  01feb2006 |          1        0.01        0.17
  12feb2006 |          1        0.01        0.18
  31mar2006 |          1        0.01        0.19
  01apr2006 |          2        0.02        0.21
  30apr2006 |          1        0.01        0.22
  31may2006 |          1        0.01        0.23
  01jun2006 |          4        0.04        0.27
  30jun2006 |          1        0.01        0.28
  01aug2006 |          2        0.02        0.30
  10aug2006 |          1        0.01        0.31
  11aug2006 |          1        0.01        0.32
  18sep2006 |          1        0.01        0.33
  01oct2006 |          1        0.01        0.34
  31oct2006 |          2        0.02        0.36
  01nov2006 |          2        0.02        0.38
  30nov2006 |          2        0.02        0.40
  01dec2006 |          1        0.01        0.41
  01jan2007 |          3        0.03        0.44
  25jan2007 |          1        0.01        0.45
  31jan2007 |          1        0.01        0.46
  01feb2007 |          2        0.02        0.48
  28feb2007 |          2        0.02        0.50
  01may2007 |          1        0.01        0.51
  23may2007 |          1        0.01        0.52
  31may2007 |          2        0.02        0.54
  30jul2007 |          1        0.01        0.55
  01aug2007 |          1        0.01        0.56
  01sep2007 |          1        0.01        0.57
  30sep2007 |          2        0.02        0.59
  20oct2007 |          1        0.01        0.60
  01nov2007 |          1        0.01        0.61
  01mar2008 |          1        0.01        0.62
  08feb2009 |          1        0.01        0.63
  31mar2009 |          1        0.01        0.64
          . |      9,936       99.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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