Frequencies for first 10,000 rows of gestat10 variable in natl1985 dataset :

  Gestation |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          9        0.09        0.09
          2 |         90        0.90        0.99
          3 |        151        1.51        2.50
          4 |        606        6.06        8.56
          5 |        320        3.20       11.76
          6 |      3,649       36.49       48.25
          7 |      2,034       20.34       68.59
          8 |      1,405       14.05       82.64
          9 |      1,492       14.92       97.56
         10 |        244        2.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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