Help - comparing percentages in programmatic survey data

#1
I am a public health researcher that usually does qualitative research and am now trying to analyze a quantitative survey (in Excel no less). Can anyone help me figure out how to compare two percentages from my results to see if they are statistically significant?

A bit of background, I surveyed 365 clients (a 5% sample, not random) but for most questions I have fewer than 365 responses because not everyone answered every question. Here is an example of one of the results I'm trying to determine if it is statistically significant.

I asked clients to rate their health status as one of five categories: bad, regular, good, very good, or excellent. I also divided the clients into categories based on age: 20 o younger, 21-40, 41-60, 61 or older. Looking specifically at the youngest and oldest clients, 29% of the youngest group rated their health as regular or bad, compared to 83% of the oldest group. I assume this is statistically significant but need to put a p-value to it when reporting my results.

Please let me know if you can help or if you need any additional information about my data to answer my question.

Thank you!