Frequencies for first 10,000 rows of obgest_flg variable in natl2006 dataset :

   Clinical |
Estimate of |
  Gestation |
  Used Flag |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        382        3.82        3.82
          . |      9,618       96.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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