Frequencies for first 10,000 rows of uca_ompha variable in natl2009 dataset :

Omphalocele |
/Gastroschi |
    sis RFP |
761=f_uca_o |
 mphalo U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |      9,986       99.86       99.91
          9 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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