Frequencies for first 10,000 rows of prov1235 variable in pos1992 dataset :

 stations - |
 peritoneal |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,900       99.00       99.00
          1 |         66        0.66       99.66
          2 |         20        0.20       99.86
          3 |          1        0.01       99.87
          4 |          6        0.06       99.93
          5 |          1        0.01       99.94
          7 |          1        0.01       99.95
          8 |          3        0.03       99.98
          9 |          1        0.01       99.99
         11 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017