Frequencies for first 10,000 rows of injpoisad variable in nhamcsed2013 dataset :

  Is visit related to injury, poisoning |
           or adverse effect of medical |
                          treatment?  U |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                  Blank |         92        0.92        0.92
                                Unknown |        270        2.70        3.62
                     Yes, injury/trauma |      3,078       30.78       34.40
                         Yes, poisoning |         85        0.85       35.25
Yes, adverse effect of medical treatmen |        204        2.04       37.29
No, visit is not related to injury, poi |      6,251       62.51       99.80
             Questionable injury status |         20        0.20      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016