Frequencies for first 10,000 rows of circul variable in natl1992 dataset :

      Other |
circulatory |
/respirator |
y anomalies |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          4        0.04        0.04
          2 |      9,993       99.93       99.97
          9 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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