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

  Prolonged |
  Labor RFP |
607=f_ol_pr |
    olong R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,163       61.63       61.63
          N |      3,811       38.11       99.74
          U |          1        0.01       99.75
          Y |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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