Dividing the total assessed value into the land value will give you the percentage of your purchase price that is usually used as the land value percentage of your purchase price.  

In the SFR 3br+ class, there has emerged a kind of dividing line around $1,800'ish per month.

They determine the property's worth based on its net operating income divided by the purchase price.

The backyard is already divided into 2 parts and has plenty of space for an ADU.

Obviously, you would need a good contract stipulating your ownership and how proceeds would be divided upon sale. 

Quote from @Mike Dymski: Until the government stops printing so much money and stealing from non asset owners through inflation, the economic divide will continue to widen, social unrest will continue to accelerate, and populism and socialism will continue to expand.As disparity gap grows wider and deeper, yeah Communisms pitch sounds better n better, right.

Butchers hill is the dividing line between desirable to the south, to some issues to the north.

Technology advances are making matters worse as the wealth divide will continue to grow.

Then divide your answer by the previous sale amount and multiple 100.

Asset owners are fine as their asset prices went up...non asset owners are not fine...and the economic divide widened a lot.