Frequencies for first 10,000 rows of cause3 variable in nhamcsopd1997 dataset :

   cause of |
  injury #3 |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,995       99.95       99.95
       8490 |          1        0.01       99.96
       8493 |          2        0.02       99.98
       8496 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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