Frequencies for first 10,000 rows of prov4180 variable in posclia2006 dataset :

  number of |
  lab sites |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,541       95.41       95.41
          1 |         30        0.30       95.71
          2 |        191        1.91       97.62
          3 |         85        0.85       98.47
          4 |         34        0.34       98.81
          5 |         21        0.21       99.02
          6 |         15        0.15       99.17
          7 |         11        0.11       99.28
          8 |          5        0.05       99.33
          9 |          7        0.07       99.40
         10 |         10        0.10       99.50
         11 |          3        0.03       99.53
         12 |          5        0.05       99.58
         13 |          2        0.02       99.60
         14 |          2        0.02       99.62
         15 |          5        0.05       99.67
         16 |          4        0.04       99.71
         17 |          3        0.03       99.74
         18 |          5        0.05       99.79
         19 |          5        0.05       99.84
         20 |          2        0.02       99.86
         22 |          1        0.01       99.87
         23 |          1        0.01       99.88
         24 |          2        0.02       99.90
         27 |          2        0.02       99.92
         31 |          1        0.01       99.93
         32 |          2        0.02       99.95
         65 |          1        0.01       99.96
         70 |          1        0.01       99.97
         90 |          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