Inventory for auto dealer

Hi, I run a small car lot, as a single member llc.  I am stumped on how to report inventory.  We generally buy cars at auction or take them in on trade, and usually recondition and service them before reselling.  So do I just put starting inventory as how many vehicles we had in stock on 1/1, and ending at how many vehicles we have in stock on 12/31?  Or is it how many we sold during the year?  Thank you