Frequencies for first 10,000 rows of workrel variable in nhamcsed1996 dataset :

             is injury work related? |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
Not applicable (not an injury visit) |      6,250       62.50       62.50
                                 Yes |        407        4.07       66.57
                                  No |      2,350       23.50       90.07
                             Unknown |        993        9.93      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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