Progress through decade by decade on separate sheets of paper. Divide the group randomly into five small groups. Give each paper and a marker. It can be advantageous to allow only a few minutes in each stage of this process for several reasons. Speed encourages the group to brainstorm and trust the collective for accuracy.
Speed also discourages the group from diverting from the task at hand.
However, cohorts of people who can be identified has having common values are generally closer to twenty years. We could debate this for hours, of course. This material suggests that people begin forming their values at about age eleven. Some people suggest that people begin forming their values at a much younger or somewhat older age, but this will work for our purposes today. Each of your groups has been assigned one of these generation cohorts, which one is written on the top of your flip chart paper.