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

      Renal |
 Agenesis U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        0.02        0.02
          2 |      8,772       87.72       87.74
          9 |      1,226       12.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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