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

Hepatitis B |
      Y Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,857       98.57       98.57
          U |        107        1.07       99.64
          Y |         36        0.36      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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