Frequencies for first 10,000 rows of pre4000 variable in natl2002 dataset :

   Previous |
     infant |
4000+ grams |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        477        4.77        4.77
          2 |      9,210       92.10       96.87
          9 |        313        3.13      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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