Frequencies for first 10,000 rows of urf_phyper variable in natlterr2003 dataset :

  Pregnancy |
 Associated |
Hypertensio |
      n U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        388        3.88        3.88
          2 |      9,587       95.87       99.75
          8 |         23        0.23       99.98
          9 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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