Frequencies for first 10,000 rows of nprevis variable in natlterr1996 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        104        1.04        1.04
          1 |         30        0.30        1.34
          2 |         87        0.87        2.21
          3 |        158        1.58        3.79
          4 |        255        2.55        6.34
          5 |        359        3.59        9.93
          6 |        564        5.64       15.57
          7 |        577        5.77       21.34
          8 |        875        8.75       30.09
          9 |        705        7.05       37.14
         10 |      1,879       18.79       55.93
         11 |        702        7.02       62.95
         12 |      1,483       14.83       77.78
         13 |        496        4.96       82.74
         14 |        576        5.76       88.50
         15 |        550        5.50       94.00
         16 |        223        2.23       96.23
         17 |         98        0.98       97.21
         18 |        108        1.08       98.29
         19 |         31        0.31       98.60
         20 |         84        0.84       99.44
         21 |         11        0.11       99.55
         22 |          8        0.08       99.63
         23 |          2        0.02       99.65
         24 |          6        0.06       99.71
         25 |         10        0.10       99.81
         26 |          2        0.02       99.83
         27 |          1        0.01       99.84
         28 |          1        0.01       99.85
         30 |          1        0.01       99.86
         31 |          1        0.01       99.87
         36 |          2        0.02       99.89
         39 |          2        0.02       99.91
         40 |          1        0.01       99.92
         45 |          1        0.01       99.93
         47 |          1        0.01       99.94
         48 |          1        0.01       99.95
         99 |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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