Frequencies for first 10,000 rows of estgest variable in natl2010 dataset :

Obstetric/C |
    linical |
  Gestation |
   Est. RFP |
573=f_cline |
     st U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          1        0.01        0.01
         22 |          4        0.04        0.05
         23 |          2        0.02        0.07
         24 |          7        0.07        0.14
         25 |          4        0.04        0.18
         26 |          7        0.07        0.25
         27 |          6        0.06        0.31
         28 |         18        0.18        0.49
         29 |         10        0.10        0.59
         30 |         22        0.22        0.81
         31 |         22        0.22        1.03
         32 |         39        0.39        1.42
         33 |         50        0.50        1.92
         34 |        100        1.00        2.92
         35 |        166        1.66        4.58
         36 |        346        3.46        8.04
         37 |        763        7.63       15.67
         38 |      1,661       16.61       32.28
         39 |      2,879       28.79       61.07
         40 |      2,680       26.80       87.87
         41 |      1,021       10.21       98.08
         42 |         85        0.85       98.93
         43 |          4        0.04       98.97
         44 |          2        0.02       98.99
         99 |        101        1.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015