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

   arterial |
blood gases |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,749       97.49       97.49
        yes |        251        2.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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