Frequencies for first 10,000 rows of nprevis variable in natl1996 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        127        1.27        1.27
          1 |         35        0.35        1.62
          2 |         74        0.74        2.36
          3 |         65        0.65        3.01
          4 |        120        1.20        4.21
          5 |        216        2.16        6.37
          6 |        283        2.83        9.20
          7 |        302        3.02       12.22
          8 |        503        5.03       17.25
          9 |        631        6.31       23.56
         10 |      1,660       16.60       40.16
         11 |        695        6.95       47.11
         12 |      1,611       16.11       63.22
         13 |        726        7.26       70.48
         14 |        760        7.60       78.08
         15 |      1,201       12.01       90.09
         16 |        289        2.89       92.98
         17 |        120        1.20       94.18
         18 |        121        1.21       95.39
         19 |         49        0.49       95.88
         20 |        173        1.73       97.61
         21 |         27        0.27       97.88
         22 |         21        0.21       98.09
         23 |         14        0.14       98.23
         24 |          9        0.09       98.32
         25 |         32        0.32       98.64
         26 |          2        0.02       98.66
         27 |          5        0.05       98.71
         28 |          1        0.01       98.72
         29 |          1        0.01       98.73
         30 |          9        0.09       98.82
         31 |          2        0.02       98.84
         32 |          1        0.01       98.85
         35 |          2        0.02       98.87
         36 |          1        0.01       98.88
         39 |          1        0.01       98.89
         40 |          3        0.03       98.92
         49 |          2        0.02       98.94
         99 |        106        1.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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