Final answer:
Based on the provided information, the middle-aged adults (30-50) age group is most likely to report an increase in stress levels over the past 5 years.
Step-by-step explanation:
According to figure 14.5, nearly half of U.S. adults reported that their stress levels have increased over the past 5 years. However, figure 14.6 shows that the greatest increase in stress levels occurred among men, Hispanic people aged 45-64, college graduates, and those with full-time employment between 2006 and 2009. Therefore, based on the provided information, the middle-aged adults (30-50) age group is most likely to report an increase in stress levels over the past 5 years.