Frequencies for first 10,000 rows of op_ecvf variable in natlterr2008 dataset :

     Failed |
   External |
   Cephalic |
Version RFP |
604=f_ob_fa |
       il R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,061       60.61       60.61
          N |      3,933       39.33       99.94
          Y |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016