Frequencies for first 10,000 rows of dgestat variable in natl1991 dataset :

Gestation - |
  Detail in |
      Weeks |      Freq.     Percent        Cum.
------------+-----------------------------------
         17 |          1        0.01        0.01
         18 |          1        0.01        0.02
         21 |          5        0.05        0.07
         22 |          5        0.05        0.12
         23 |          7        0.07        0.19
         24 |         12        0.12        0.31
         25 |         18        0.18        0.49
         26 |         21        0.21        0.70
         27 |         25        0.25        0.95
         28 |         19        0.19        1.14
         29 |         24        0.24        1.38
         30 |         36        0.36        1.74
         31 |         63        0.63        2.37
         32 |         71        0.71        3.08
         33 |        106        1.06        4.14
         34 |        183        1.83        5.97
         35 |        254        2.54        8.51
         36 |        386        3.86       12.37
         37 |        695        6.95       19.32
         38 |      1,287       12.87       32.19
         39 |      2,012       20.12       52.31
         40 |      2,080       20.80       73.11
         41 |      1,396       13.96       87.07
         42 |        615        6.15       93.22
         43 |        296        2.96       96.18
         44 |        203        2.03       98.21
         45 |         86        0.86       99.07
         46 |         50        0.50       99.57
         47 |         28        0.28       99.85
         99 |         15        0.15      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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