First, the link should probably be to the full report

https://www.kaggle.com/nomilk/data-science-language-and-job-...

Second, this is data scraped from Australian job listings. So the title should probably reflect that.

Lastly, this data seems a little odd. You’ve got month-to-month swings of 20% or more happening here. This data source seems extremely noisy and I don’t think there’s anything you can reliably say about a trend here.

I think others in the comments have pointed out why, if it were real, you might see this overall trend and why it doesn’t mean salaries for the same role are falling.

This looks like a fun side project, but I would be careful reading anything into the results.