Frequencies for first 10,000 rows of bwtimp variable in linkpe2009psden dataset :

    Imputed |
Birthweight |
     Flag U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         27        0.27        0.27
          . |      9,973       99.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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