Frequencies for first 10,000 rows of prov4180 variable in posclia2009 dataset :

  number of |
  lab sites |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,595       95.95       95.95
          2 |        180        1.80       97.75
          3 |         78        0.78       98.53
          4 |         32        0.32       98.85
          5 |         22        0.22       99.07
          6 |         13        0.13       99.20
          7 |         12        0.12       99.32
          8 |          7        0.07       99.39
          9 |          6        0.06       99.45
         10 |          7        0.07       99.52
         11 |          2        0.02       99.54
         12 |          7        0.07       99.61
         13 |          2        0.02       99.63
         14 |          2        0.02       99.65
         15 |          5        0.05       99.70
         16 |          2        0.02       99.72
         17 |          4        0.04       99.76
         18 |          2        0.02       99.78
         19 |          4        0.04       99.82
         20 |          2        0.02       99.84
         21 |          1        0.01       99.85
         22 |          2        0.02       99.87
         23 |          1        0.01       99.88
         24 |          2        0.02       99.90
         27 |          2        0.02       99.92
         32 |          2        0.02       99.94
         43 |          1        0.01       99.95
         65 |          1        0.01       99.96
         70 |          1        0.01       99.97
         75 |          1        0.01       99.98
        138 |          1        0.01       99.99
        315 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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