Frequencies for first 10,000 rows of me_trial variable in natlterr2014 dataset 

   Trial of |
      Labor |
  Attempted |
        (if |
cesarean) Y |
        Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,077       10.77       10.77
          N |      2,065       20.65       31.42
          U |        442        4.42       35.84
          X |      5,530       55.30       91.14
          Y |        886        8.86      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016