Does anyone know how time is measured across each era?

For example, on the official site is says the following:

"In the Year 1557 of the Sixth Astral Era, a mere thirty-six years from the Empire's founding..."

Have they ever specified if years begin their count anew in each era, or if it is a comprehensive total? Will the 7th Umbra Era begin with year 1 or will it continue with the last year of the previous cycle?

Thanks for the clarification, it was just something that came to mind recently.