Frequencies for first 10,000 rows of op_ruptr variable in natlterr2010 dataset :

  Premature |
 Rupture of |
   Membrane |
        RFP |
605=f_ol_ru |
    pture R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      4,656       46.56       46.56
          N |      4,274       42.74       89.30
          U |        993        9.93       99.23
          Y |         77        0.77      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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