Frequencies for first 10,000 rows of workrel variable in namcs1998 dataset :

             is injury work related? |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                                 Yes |        160        1.60        1.60
                                  No |        323        3.23        4.83
                             Unknown |        496        4.96        9.79
Not applicable (not an injury visit) |      9,021       90.21      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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