Frequencies for first 10,000 rows of amb variable in nhamcsopd2004 dataset :

    were surgical |
       procedures |
     ord/sched or |
            perf? |      Freq.     Percent        Cum.
------------------+-----------------------------------
               no |      9,329       93.29       93.29
              yes |        671        6.71      100.00
------------------+-----------------------------------
            Total |     10,000      100.00

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