Frequencies for first 10,000 rows of combgest variable in natlterr2003 dataset :

Gestation - |
  Detail in |
  Weeks U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
         21 |          1        0.01        0.01
         22 |          4        0.04        0.05
         23 |          4        0.04        0.09
         24 |          8        0.08        0.17
         25 |         12        0.12        0.29
         26 |         10        0.10        0.39
         27 |         13        0.13        0.52
         28 |         20        0.20        0.72
         29 |         26        0.26        0.98
         30 |         29        0.29        1.27
         31 |         47        0.47        1.74
         32 |         87        0.87        2.61
         33 |        115        1.15        3.76
         34 |        210        2.10        5.86
         35 |        355        3.55        9.41
         36 |        782        7.82       17.23
         37 |      1,676       16.76       33.99
         38 |      2,648       26.48       60.47
         39 |      2,189       21.89       82.36
         40 |      1,312       13.12       95.48
         41 |        288        2.88       98.36
         42 |        104        1.04       99.40
         43 |         53        0.53       99.93
         44 |          2        0.02       99.95
         99 |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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