Frequencies for first 10,000 rows of ip_hepatb variable in natl2016 dataset :

Hepatitis B |
      Y Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,872       98.72       98.72
          U |         89        0.89       99.61
          Y |         39        0.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 4 Oct 2017