Frequencies for first 10,000 rows of prov1945 variable in pos1991 dataset :

        320 |
 urinalysis |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,536       85.36       85.36
          N |        572        5.72       91.08
          Y |        892        8.92      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016