Frequencies for first 10,000 rows of obgest_flg variable in natlterr2003 dataset :

   Clinical |
Estimate of |
  Gestation |
  Used Flag |
       U;R  |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        129        1.29        1.29
          . |      9,871       98.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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