According to that then it looks like the 12 month running average is significantly lower, is that to be expected/in line with predictions/at all statistically r

According to that then it looks like the 12 month running average is significantly lower, is that to be expected/in line with predictions/at all statistically relevant? I'm still not sure I actually understand what those numbers represent. EDIT: After jacobolus updated with more columns and checking some other years from the link provided, that does not actually appear to be a trend. My apologies.