Frequencies for first 10,000 rows of injpoisad variable in nhamcsed2012 dataset :

  Is visit related to injury, poisoning |
           or adverse effect of medical |
                          treatment?  U |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                                  Blank |         57        0.57        0.57
                                Unknown |        494        4.94        5.51
                     Yes, injury/trauma |      3,101       31.01       36.52
                         Yes, poisoning |        114        1.14       37.66
Yes, adverse effect of medical treatmen |        221        2.21       39.87
No, visit is not related to injury, poi |      5,984       59.84       99.71
             Questionable injury status |         29        0.29      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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