Frequencies for first 10,000 rows of ngtube variable in nhamcsed2008 dataset :

         ng |
tube/gastri |
   c lavage |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,975       99.75       99.75
        yes |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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