Frequencies for first 10,000 rows of gestat10 variable in natl1986 dataset :

  Gestation |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.07        0.07
          2 |         81        0.81        0.88
          3 |        135        1.35        2.23
          4 |        503        5.03        7.26
          5 |        378        3.78       11.04
          6 |      3,684       36.84       47.88
          7 |      1,973       19.73       67.61
          8 |      1,398       13.98       81.59
          9 |      1,487       14.87       96.46
         10 |        354        3.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016