Frequencies for first 10,000 rows of uca_nerv variable in natlterr2005 dataset :

      Other |
    Central |
    Nervous |
     System |
Anomalies U |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |      4,503       45.03       45.03
          9 |      1,752       17.52       62.55
          . |      3,745       37.45      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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