Frequencies for first 10,000 rows of effective_date variable in nadac20170614 dataset :

  Effective |
Date of the |
  NADAC Per |
  Unit Cost |      Freq.     Percent        Cum.
------------+-----------------------------------
  18may2016 |         33        0.33        0.33
  01jun2016 |          1        0.01        0.34
  15jun2016 |          4        0.04        0.38
  22jun2016 |         26        0.26        0.64
  23jun2016 |          1        0.01        0.65
  01jul2016 |          4        0.04        0.69
  12jul2016 |          1        0.01        0.70
  13jul2016 |          1        0.01        0.71
  20jul2016 |         31        0.31        1.02
  10aug2016 |          1        0.01        1.03
  17aug2016 |         48        0.48        1.51
  26aug2016 |          1        0.01        1.52
  02sep2016 |          2        0.02        1.54
  21sep2016 |         39        0.39        1.93
  23sep2016 |          5        0.05        1.98
  01oct2016 |          1        0.01        1.99
  12oct2016 |          1        0.01        2.00
  13oct2016 |          3        0.03        2.03
  19oct2016 |        108        1.08        3.11
  09nov2016 |          1        0.01        3.12
  23nov2016 |         66        0.66        3.78
  01dec2016 |          2        0.02        3.80
  14dec2016 |          4        0.04        3.84
  21dec2016 |         83        0.83        4.67
  26dec2016 |         15        0.15        4.82
  31dec2016 |          7        0.07        4.89
  01jan2017 |        148        1.48        6.37
  02jan2017 |          2        0.02        6.39
  04jan2017 |         77        0.77        7.16
  06jan2017 |         18        0.18        7.34
  09jan2017 |          4        0.04        7.38
  16jan2017 |          1        0.01        7.39
  18jan2017 |         93        0.93        8.32
  19jan2017 |          1        0.01        8.33
  23jan2017 |          3        0.03        8.36
  08feb2017 |          2        0.02        8.38
  17feb2017 |          1        0.01        8.39
  22feb2017 |        387        3.87       12.26
  23feb2017 |          2        0.02       12.28
  02mar2017 |          1        0.01       12.29
  08mar2017 |          4        0.04       12.33
  15mar2017 |          3        0.03       12.36
  17mar2017 |          1        0.01       12.37
  22mar2017 |        229        2.29       14.66
  23mar2017 |          3        0.03       14.69
  29mar2017 |          2        0.02       14.71
  01apr2017 |          3        0.03       14.74
  03apr2017 |          5        0.05       14.79
  05apr2017 |          8        0.08       14.87
  07apr2017 |          4        0.04       14.91
  12apr2017 |          4        0.04       14.95
  19apr2017 |        273        2.73       17.68
  24apr2017 |         11        0.11       17.79
  26apr2017 |          1        0.01       17.80
  02may2017 |         40        0.40       18.20
  03may2017 |          7        0.07       18.27
  10may2017 |          5        0.05       18.32
  16may2017 |          2        0.02       18.34
  17may2017 |      7,778       77.78       96.12
  24may2017 |          4        0.04       96.16
  31may2017 |         24        0.24       96.40
  01jun2017 |        235        2.35       98.75
  07jun2017 |         16        0.16       98.91
  08jun2017 |         66        0.66       99.57
  14jun2017 |         43        0.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 10 Feb 2018