Frequencies for first 10,000 rows of op_ecvf variable in natlterr2006 dataset :

     Failed |
   External |
   Cephalic |
Version RFP |
604=f_ob_fa |
       il R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,275       62.75       62.75
          N |      3,720       37.20       99.95
          Y |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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