Frequencies for first 10,000 rows of mar_imp variable in natl2007 dataset :

   Mother's |
    Marital |
     Status |
    Imputed |
   Flag U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          3        0.03        0.03
          . |      9,997       99.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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