Frequencies for first 10,000 rows of uca_heart variable in natl2003 dataset :

      Heart |
malformatio |
       ns U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |      9,039       90.39       90.44
          8 |          8        0.08       90.52
          9 |        948        9.48      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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