Where is my usage history data from last year?

I just got my water bill for July/August, and I want to compare my detailed per-zone usage during this billing period with the same period last year.

When I tried to download my usage history for each zone, I find the CSV file with dates going back to 2016, but all the usage hours/gallons are zero prior to one year ago today.

Where is the rest of my historic data, and how can I download all of it?