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

      Other |
Circulatory |
/Respirator |
y Anomalies |
          U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          7        0.07        0.07
          2 |      8,767       87.67       87.74
          9 |      1,226       12.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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