Frequencies for first 10,000 rows of inj_sev variable in person dataset :

     Injury |
   Severity |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,909       19.09       19.09
          1 |        561        5.61       24.70
          2 |      1,330       13.30       38.00
          3 |      1,704       17.04       55.04
          4 |      4,472       44.72       99.76
          5 |         10        0.10       99.86
          9 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016