Frequencies for first 10,000 rows of gestat10 variable in natl1997 dataset :

  Gestation |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |         97        0.97        1.02
          3 |        159        1.59        2.61
          4 |        725        7.25        9.86
          5 |        501        5.01       14.87
          6 |      4,618       46.18       61.05
          7 |      1,848       18.48       79.53
          8 |      1,012       10.12       89.65
          9 |      1,028       10.28       99.93
         10 |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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