GMAT Critical Reasoning (CR) | In 1987 sinusitis was the most common chronic medical

Here's my take on this question, please let me know if I am wrong.

In short, we could extract some information from the question.
1. Sinusitis is an chronicle disease followed by HBP and Arthritis.
2. The incidence rate of HBP and Arthritis will increase as patient gets order.
3. The incidence rate for Sinusitis remain the same.
4. The average age will increase between 1987 and 2000.

Question stem:
Which of the following conclusions can be most properly drawn about chronic medical conditions
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