Frequencies for first 10,000 rows of nprevis variable in natl1997 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         88        0.88        0.88
          1 |         39        0.39        1.27
          2 |         57        0.57        1.84
          3 |         77        0.77        2.61
          4 |        107        1.07        3.68
          5 |        194        1.94        5.62
          6 |        265        2.65        8.27
          7 |        271        2.71       10.98
          8 |        488        4.88       15.86
          9 |        534        5.34       21.20
         10 |      1,310       13.10       34.30
         11 |        835        8.35       42.65
         12 |      1,589       15.89       58.54
         13 |        699        6.99       65.53
         14 |        964        9.64       75.17
         15 |      1,455       14.55       89.72
         16 |        343        3.43       93.15
         17 |        154        1.54       94.69
         18 |        112        1.12       95.81
         19 |         51        0.51       96.32
         20 |        142        1.42       97.74
         21 |         32        0.32       98.06
         22 |         23        0.23       98.29
         23 |          9        0.09       98.38
         24 |          6        0.06       98.44
         25 |         27        0.27       98.71
         26 |          3        0.03       98.74
         27 |          6        0.06       98.80
         28 |          7        0.07       98.87
         29 |          2        0.02       98.89
         30 |         13        0.13       99.02
         33 |          1        0.01       99.03
         35 |          4        0.04       99.07
         36 |          2        0.02       99.09
         38 |          1        0.01       99.10
         40 |          3        0.03       99.13
         49 |          3        0.03       99.16
         99 |         84        0.84      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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