Michigan Behavioral Risk Factor Survey Tables Statewide telephone survey results detailing the prevalence of behaviors, medical conditions, and preventive health practices of Michigan residents 18 years and older. Part of the national CDC Behavioral Risk Factor Surveillance System. These reports are combined results from several years of surveys and include results from the Branch-Hillsdale-St. Joseph region. There are not enough surveys performed in each of our counties separately to have county level data. Surveying adults at the County level is extremely expensive and the CHA does not participate in the BRFS at the single county level.