Frequencies for additionalcoverageofferedin variable in snp2016 dataset :

 Additional |
   Coverage |
 Offered in |
    the Gap |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      7,809       92.90       92.90
        Yes |        597        7.10      100.00
------------+-----------------------------------
      Total |      8,406      100.00

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