Flow Totalizer - Last Year Total

I am creating a template for pump flowrates that totalizes flow at daily, monthly, yearly intervals. On top of that, I am creating tags for yesterdays total, last months total, and last years total.

I am able to make tags with correct logic for all of the except last years total. This is because there is no BOY (beginning of year) built-in-function like there is for BOM or BOD. I'm wondering if there is a way I can create logic that avoids this.

For reference, this is the logic for yesterdays total, last months total:

PreviousDay

If (Hour('*')=0 And Day('*')=1 And Month('*')=1)
Then
    TagTot('Flow Value (Cleansed)', '*-1y', '*', 90)*24
Else
    TagTot('Flow Value (Cleansed)', BOM('Jan'), '*', 90)*24

PreviousMonth

If(Hour('*-1mo')=0 And Day('*-1mo')=1)

Then TagTot('Flow Value (Cleansed)', '*-2mo', '*-1mo',90)*24

Else TagTot('Flow Value (Cleansed)', BOM('*-1mo'), BOM('*'),90)*24

YearlyTotalizer

If (Hour('*')=0 And Day('*')=1 And Month('*')=1)

Then

  TagTot('Flow Value (Cleansed)', '*-1y', '*', 90)*24

Else

  TagTot('Flow Value (Cleansed)', BOM('Jan'), '*', 90)*24