I don’t see the difference. One permil is 1/1000th of a dollar. One mill is a 1/1000th of a dollar. Is “permil” (‰) just not a common term outside my area?
While it makes perfect sense by analogy, a “permil” as a single word analogous to percent is totally unknown outside your area, if I do not miss my guess.
And as someone who lost my home to vicious misuse of property taxation (courtesy of a county supervisor who greatly disliked me), I can testify that three years is more than enough when a local government decides it wants to take your house.