Frequencies for first 10,000 rows of microce variable in natlterr2002 dataset :

Microcephal |
         us |      Freq.     Percent        Cum.
------------+-----------------------------------
          2 |      9,984       99.84       99.84
          8 |         14        0.14       99.98
          9 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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