Frequencies for first 10,000 rows of combgest variable in natlterr2014 dataset 

   Combined |
Gestation - |
  Detail in |
Weeks 17-47 |
       17th |
    through |
  47th week |
         of |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          2        0.02        0.02
         21 |          2        0.02        0.04
         22 |          3        0.03        0.07
         23 |          5        0.05        0.12
         24 |          7        0.07        0.19
         25 |          9        0.09        0.28
         26 |         13        0.13        0.41
         27 |         10        0.10        0.51
         28 |         16        0.16        0.67
         29 |         32        0.32        0.99
         30 |         38        0.38        1.37
         31 |         50        0.50        1.87
         32 |         66        0.66        2.53
         33 |         95        0.95        3.48
         34 |        191        1.91        5.39
         35 |        251        2.51        7.90
         36 |        473        4.73       12.63
         37 |        943        9.43       22.06
         38 |      1,811       18.11       40.17
         39 |      2,261       22.61       62.78
         40 |      1,402       14.02       76.80
         41 |        594        5.94       82.74
         42 |        274        2.74       85.48
         43 |        162        1.62       87.10
         44 |         94        0.94       88.04
         45 |         50        0.50       88.54
         46 |         33        0.33       88.87
         47 |         10        0.10       88.97
         99 |      1,103       11.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016