RV-12 E-LSA depreciation

Here is a question brought by my property tax filing due soon:
What kind of yearly depreciation do you apply to your RV-12 E-LSA taxable asset value?
Another way to look at this is what is the life span of the asset regarding it's full depreciation?
I am bidding here for the shortest life span acceptable by taxing authorities

JP, I keep my RV at KTTA in Lee County. They look at the Januarry issue of Trade-A-Plane and other aviation pubs to try and determin selling price. They are completely unaware of differences in E-AB aircraft. I was successful in lowering their appraised value of my aircraft buy having them come out to the airport, looking at the aircraft, explaining what E-AB was and how no two are alike. Also, I was able to explain how the tail feathers were 15 years old, one wing was 14 years old, the other wing was 13 years old, etc. They ended up accepting my estimate of a declared value.