Frequencies for first 10,000 rows of nprevis variable in natlterr1997 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        114        1.14        1.14
          1 |         35        0.35        1.49
          2 |         87        0.87        2.36
          3 |        162        1.62        3.98
          4 |        247        2.47        6.45
          5 |        382        3.82       10.27
          6 |        502        5.02       15.29
          7 |        672        6.72       22.01
          8 |        857        8.57       30.58
          9 |        749        7.49       38.07
         10 |      2,016       20.16       58.23
         11 |        606        6.06       64.29
         12 |      1,468       14.68       78.97
         13 |        427        4.27       83.24
         14 |        532        5.32       88.56
         15 |        597        5.97       94.53
         16 |        186        1.86       96.39
         17 |         94        0.94       97.33
         18 |        112        1.12       98.45
         19 |         34        0.34       98.79
         20 |         65        0.65       99.44
         21 |         16        0.16       99.60
         22 |          8        0.08       99.68
         23 |          6        0.06       99.74
         24 |          4        0.04       99.78
         25 |          7        0.07       99.85
         26 |          1        0.01       99.86
         28 |          3        0.03       99.89
         30 |          1        0.01       99.90
         33 |          1        0.01       99.91
         41 |          1        0.01       99.92
         49 |          1        0.01       99.93
         99 |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015