Frequencies for first 10,000 rows of injury variable in nhamcsopd1998 dataset :

    is this |
      visit |
 related to |
  injury or |
 poisoning? |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,125       91.25       91.25
          1 |        875        8.75      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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