Saving Custom Number Formats Across Workbooks for Dollars and Units

I work in marketing and am frequently formatting my cells with the custom number format to make it easier to read units and dollars.

Currently I am just copying and pasting into the custom formatting bar each time I create a new workbook. Does anyone know of a way to save this formatting so each time I open a new workbook it is already in the dropdown menu?

Units with thousand, million, or billion labeling:

[<999950]0.0,"K";[<999950000]0.0,,"M";0.0,,,"B"

Dollars with thousand, million, or billion labeling:

[<999950]$0.0,"K";[<999950000]$0.0,,"M";$0.0,,,"B"