Frequencies for first 10,000 rows of ab_nicu variable in natl2014 dataset :

  Admission |
  to NICU Y |
        Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      8,995       89.95       89.95
          U |        269        2.69       92.64
          Y |        736        7.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016