Frequencies for first 10,000 rows of uca_circ variable in natl2005 dataset :

      Other |
Circulatory |
/Respirator |
y Anomalies |
          U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |      9,855       98.55       98.60
          9 |        140        1.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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