RowID --> observer identifiant Age --> 2,3, or 4 corresponding to a range age of [16-25],[26-45] and over 45, respectively Gender --> 1, 2 corresponding to male or female, respectively Frequency-dive --> 1,2, or 3 corresponding to Never, Occasionally or Very often, respectively Diving_other_GBR --> 1,2, or 3 corresponding to Yes, No or not a diver, respectively Group --> --> 1,2, or 3 corresponding to a Marine Scientist, Experienced diver or Citizen, respectively