You're looking at 4-5 data points across an entire year? Or does your chart actually show monthly/weekly/daily fluctuations?

Edit: I apologize, you looked at 1 week ranges. That helps a little with the fluctuations of days, but again, cherry picking weeks like this is not a valid form of trending analysis...

You've cherry picked 4-5 dates that may be the same weekday or may not be the same weekday. If you're comparing Monday vs Saturday vs Wednesday, you're going to see somewhat / drastically different results.

You also picked USA's Halloween, which is a terrible choice. Postings on that date historically are lower than other days that fall on the same day of week.

I appreciate the effort, however, you're not providing enough clarity and consistency.. the only valid dates you can actually consider for an analysis like this are Jan 31 and Jan 31, however, as they're likely on different days of the week, you can't rely too heavily on those direct comparisons either ...