Frequencies for first 10,000 rows of paydk variable in namcs2008 dataset :

    unknown |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,728       97.28       97.28
        yes |        272        2.72      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016