This seems like an abnormally high connections/IP, even if we assume some of the IPs represent multiple clients. Perhaps it's because of retrying as the author does not seem to have sent NTP replies back?
What seems stranger to me is the incorrect clock settings on 30% of those computers. Why do they all think it's the end of September (even though the years are drastically different)?
I suspect this is just because the author is sorting the text, and the days at the end of September are lexicographically last given that date formatting.