Answer:
Step-by-step explanation:
If the price is supposed to be dropping with each year, maybe your year/price chart would reflect that. Seems to me that the price rose between 2015 and 2016 and even by 2017 the value was still higher than it was in 2015.
I have no way of knowing how to fix this.
Let's ASSUME that the 2015 price was $71,445 and that the 2016 and 2017 prices are valid.
the decrease between 2015 and 2016 is (71445 - 68640) / 71445 = 0.03926
or 3.926%
the decrease between 2016 and 2017 is (68640 - 65945)/68640 = 0.03926
or 3.926%
so the price each year after new is
p = 71445(1 - 0.03926)ⁿ
or
71445(0.96074)ⁿ
where n is the number of years.
To get the monthly version, we divide the decrease by 12
p = 71445(1 - 0.03926/12)ˣ
or
p = 71445(1 - 0.00327)ˣ
or
p = 71445(0.99673)ˣ
where x is the number of months since new.
This may not be your exact answer, but the same method can be used if you get real numbers.
