Frequencies for first 10,000 rows of gestat10 variable in natl1983 dataset :

  Gestation |
  Recode 10 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         10        0.10        0.10
          2 |         95        0.95        1.05
          3 |        148        1.48        2.53
          4 |        585        5.85        8.38
          5 |        356        3.56       11.94
          6 |      3,534       35.34       47.28
          7 |      2,078       20.78       68.06
          8 |      1,449       14.49       82.55
          9 |      1,544       15.44       97.99
         10 |        201        2.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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