Frequencies for first 10,000 rows of uca_nerv variable in natlterr2006 dataset :

      Other |
    Central |
    Nervous |
     System |
  Anomalies |
        RFP |
756=f_uca_n |
   ervous U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        0.02        0.02
          2 |      4,782       47.82       47.84
          9 |      1,491       14.91       62.75
          . |      3,725       37.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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