Frequencies for first 10,000 rows of uab_venl30 variable in natl2003 dataset :

   Assisted |
Ventilation |
 < 30 min U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        510        5.10        5.10
          2 |      8,579       85.79       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