Frequencies for first 10,000 rows of uca_heart variable in natl2004 dataset :

      Heart |
malformatio |
       ns U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         13        0.13        0.13
          2 |      8,761       87.61       87.74
          9 |      1,226       12.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016