Frequencies for first 10,000 rows of amb variable in nhamcsopd2003 dataset :

    were surgical |
       procedures |
     ord/sched or |
            perf? |      Freq.     Percent        Cum.
------------------+-----------------------------------
               no |      8,747       87.47       87.47
              yes |      1,253       12.53      100.00
------------------+-----------------------------------
            Total |     10,000      100.00

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