Frequencies for first 10,000 rows of dgestat variable in natl2002 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         19 |          1        0.01        0.01
         21 |          5        0.05        0.06
         22 |          2        0.02        0.08
         23 |          2        0.02        0.10
         24 |          8        0.08        0.18
         25 |          5        0.05        0.23
         26 |          8        0.08        0.31
         27 |         10        0.10        0.41
         28 |         13        0.13        0.54
         29 |         15        0.15        0.69
         30 |         13        0.13        0.82
         31 |         27        0.27        1.09
         32 |         58        0.58        1.67
         33 |         88        0.88        2.55
         34 |        136        1.36        3.91
         35 |        178        1.78        5.69
         36 |        396        3.96        9.65
         37 |        795        7.95       17.60
         38 |      1,729       17.29       34.89
         39 |      2,494       24.94       59.83
         40 |      2,210       22.10       81.93
         41 |      1,209       12.09       94.02
         42 |        345        3.45       97.47
         43 |        112        1.12       98.59
         44 |         44        0.44       99.03
         45 |         27        0.27       99.30
         46 |         12        0.12       99.42
         47 |         11        0.11       99.53
         99 |         47        0.47      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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