Frequencies for first 10,000 rows of effective_date variable in nadac20170524 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 |         27        0.27        0.65
  23jun2016 |         13        0.13        0.78
  01jul2016 |          4        0.04        0.82
  12jul2016 |          1        0.01        0.83
  13jul2016 |          1        0.01        0.84
  20jul2016 |         33        0.33        1.17
  10aug2016 |          1        0.01        1.18
  17aug2016 |         49        0.49        1.67
  26aug2016 |          1        0.01        1.68
  02sep2016 |          2        0.02        1.70
  21sep2016 |         42        0.42        2.12
  23sep2016 |          5        0.05        2.17
  01oct2016 |          1        0.01        2.18
  12oct2016 |          1        0.01        2.19
  13oct2016 |          3        0.03        2.22
  19oct2016 |        112        1.12        3.34
  09nov2016 |          1        0.01        3.35
  23nov2016 |         70        0.70        4.05
  01dec2016 |          2        0.02        4.07
  14dec2016 |          4        0.04        4.11
  21dec2016 |         85        0.85        4.96
  26dec2016 |         15        0.15        5.11
  31dec2016 |          7        0.07        5.18
  01jan2017 |        290        2.90        8.08
  02jan2017 |          2        0.02        8.10
  04jan2017 |         78        0.78        8.88
  06jan2017 |         18        0.18        9.06
  09jan2017 |          4        0.04        9.10
  16jan2017 |          1        0.01        9.11
  18jan2017 |         99        0.99       10.10
  19jan2017 |          1        0.01       10.11
  23jan2017 |          3        0.03       10.14
  08feb2017 |          2        0.02       10.16
  17feb2017 |          1        0.01       10.17
  22feb2017 |        478        4.78       14.95
  23feb2017 |          2        0.02       14.97
  02mar2017 |          1        0.01       14.98
  08mar2017 |          4        0.04       15.02
  15mar2017 |          3        0.03       15.05
  17mar2017 |          1        0.01       15.06
  22mar2017 |        258        2.58       17.64
  23mar2017 |          3        0.03       17.67
  29mar2017 |          2        0.02       17.69
  01apr2017 |          2        0.02       17.71
  03apr2017 |          5        0.05       17.76
  05apr2017 |          8        0.08       17.84
  07apr2017 |          4        0.04       17.88
  12apr2017 |          4        0.04       17.92
  19apr2017 |        304        3.04       20.96
  24apr2017 |         11        0.11       21.07
  26apr2017 |          1        0.01       21.08
  02may2017 |         40        0.40       21.48
  03may2017 |          7        0.07       21.55
  10may2017 |          5        0.05       21.60
  17may2017 |      7,836       78.36       99.96
  24may2017 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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