A series of national surveys on stress were conducted in 1983, 2006, and 2009. The data revealed the following trends based on employment status:

• Unemployed: Reported the highest stress levels, which peaked in 2006 and then declined by 2009.
• Retired: Consistently reported the lowest stress levels, which remained stable across all three surveys.
• Full-time employed: Experienced a steady increase in stress from 1983 to 2009.
• Part-time employed: Saw stress levels rise until 2006 and then decrease by 2009.

Based on this information, which of the following statements represents the most accurate analysis of the relationship between these trends?