Frequencies for first 10,000 rows of obgest_flg variable in natlterr2015 dataset :

  Obstetric |
Estimate of |
  Gestation |
  Used Flag |
      Blank |
  Obstetric |
Estimate is |
      not u |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,646       16.46       16.46
          . |      8,354       83.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Oct 2016