$6-21.$ The Centers for Disease Control and Prevention Office on Smoking and Health $($OSH$)$ is the lead federal agency responsible for comprehensive tobacco prevention and control. OSH was established in $1965$ to reduce the death and disease caused by tobacco use and exposure to secondhand smoke. One of the many responsibilities of the OSH is to collect data on tobacco use. The following data show the percentage of U$.$S$.$ adults who were users of tobacco for a recent $11-$year period. Year Precentage of Adults Who Smoke $123222\mathrm{.}2321\mathrm{.}5420\mathrm{.}8520\mathrm{.}8620\mathrm{.}5719\mathrm{.}48\mathrm{.}20\mathrm{.}5920\mathrm{.}41018\mathrm{.}21118\mathrm{.}1$