Frequencies for first 10,000 rows of prov1235 variable in pos1993 dataset :

 stations - |
 peritoneal |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,889       98.89       98.89
          1 |         75        0.75       99.64
          2 |         21        0.21       99.85
          3 |          2        0.02       99.87
          4 |          6        0.06       99.93
          5 |          1        0.01       99.94
          7 |          1        0.01       99.95
          8 |          2        0.02       99.97
          9 |          1        0.01       99.98
         10 |          1        0.01       99.99
         11 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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