Frequencies for first 10,000 rows of rf_ppoutc variable in natlterr2007 dataset :

       Poor |
  Pregnancy |
Outcome RFP |
588=f_rf_pp |
        o R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,163       61.63       61.63
          N |      3,820       38.20       99.83
          U |          1        0.01       99.84
          Y |         16        0.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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