Frequencies for first 10,000 rows of rf_inftr variable in natl2017 dataset :

Infertility |
  Treatment |
 Used Y Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,827       98.27       98.27
          U |         90        0.90       99.17
          Y |         83        0.83      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Sep 2018