Frequencies for first 10,000 rows of vworkrel variable in nhamcsed2006 dataset :

   is visit |
       work |
   related? |      Freq.     Percent        Cum.
------------+-----------------------------------
      blank |        305        3.05        3.05
        yes |        276        2.76        5.81
         no |      9,050       90.50       96.31
    unknown |        369        3.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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