Frequencies for first 10,000 rows of uab_ven30m variable in natl2003 dataset :

   Assisted |
Ventilation |
>= 30 min U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         99        0.99        0.99
          2 |      8,990       89.90       90.89
          8 |          7        0.07       90.96
          9 |        904        9.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015