Frequencies for first 10,000 rows of urf_phyper variable in natl2010 dataset :

  Pregnancy |
 Associated |
Hypertensio |
      n RFP |
689=f_urf_p |
  hyper U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        507        5.07        5.07
          2 |      8,404       84.04       89.11
          9 |      1,089       10.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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