Frequencies for first 10,000 rows of prov1235 variable in pos1995 dataset :

 stations - |
 peritoneal |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,873       98.73       98.73
          1 |         84        0.84       99.57
          2 |         24        0.24       99.81
          3 |          3        0.03       99.84
          4 |          7        0.07       99.91
          5 |          2        0.02       99.93
          7 |          1        0.01       99.94
          8 |          2        0.02       99.96
          9 |          1        0.01       99.97
         10 |          1        0.01       99.98
         11 |          1        0.01       99.99
         13 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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